Tổng hợp topic Technology (Computer, Science,...) IELTS READING (PDF)(Phần 2)

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II. Tổng hợp topic Technology (Computer, Science,...) IELTS READING (PDF)

16. Bài 16

The Birth of Scientific English

World science is dominated today by a small number of languages, including Japanese, German and French, but it is English which is probably the most popular global language of science. This is not just because of the importance of English-speaking countries such as the USA in scientific research; the scientists of many non-English-speaking countries find that they need to write their research papers in English to reach a wide international audience. Given the prominence of scientific English today, it may seem surprising that no one really knew how to write science in English before the 17th century. Before that, Latin was regarded as the lingua franca1 for European intellectuals.

The European Renaissance (c. 14th-16th century) is sometimes called the 'revival of learning', a time of renewed interest in the 'lost knowledge' of classical times. At the same time, however, scholars also began to test and extend this knowledge. The emergent nation states of Europe developed competitive interests in world exploration and the development of trade. Such expansion, which was to take the English language west to America and east to India, was supported by scientific developments such as the discovery of magnetism (and hence the invention of the compass), improvements in cartography and - perhaps the most important scientific revolution of them all - the new theories of astronomy and the movement of the Earth in relation to the planets and stars, developed by Copernicus (1473-1543).

England was one of the first countries where scientists adopted and publicised Copernican ideas with enthusiasm. Some of these scholars, including two with interests in language - John Wall's and John Wilkins - helped found the Royal Society in 1660 in order to promote empirical scientific research.

Across Europe similar academies and societies arose, creating new national traditions of science. In the initial stages of the scientific revolution, most publications in the national languages were popular works, encyclopaedias, educational textbooks and translations.

Original science was not done in English until the second half of the 17th century. For example, Newton published his mathematical treatise, known as the Principia, in Latin, but published his later work on the properties of light - Opticks - in English.

There were several reasons why original science continued to be written in Latin. The first was simply a matter of audience. Latin was suitable for an international audience of scholars, whereas English reached a socially wider, but more local, audience. Hence, popular science was written in English.
A second reason for writing in Latin may, perversely, have been a concern for secrecy. Open publication had dangers in putting into the public domain preliminary ideas which had not yet been fully exploited by their 'author'. This growing concern about intellectual properly rights was a feature of the period - it reflected both the humanist notion of the individual, rational scientist who invents and discovers through private intellectual labour, and the growing connection between original science and commercial exploitation. There was something of a social distinction between 'scholars and gentlemen' who understood Latin, and men of trade who lacked a classical education. And in the mid-17th century it was common practice for mathematicians to keep their discoveries and proofs secret, by writing them in cipher, in obscure languages, or in private messages deposited in a sealed box with the Royal Society. Some scientists might have felt more comfortable with Latin precisely because its audience, though in national, was socially restricted. Doctors clung the most keenly to Latin as an 'insider language'.

A third reason why the writing of original science in English was delayed may have been to do with the linguistic inadequacy of English in the early modern period. English was not well equipped to deal with the scientific argument. First, it lacked the necessary technical vocabulary. Second, it lacked the grammatical resources required to represent the world in an objective and impersonal way, and to discuss the relations, such as cause and effect, that might hold between complex and hypothetical entities.

Fortunately, several members of the Royal Society possessed an interest in language and became engaged in various linguistic projects. Although a proposal in 1664 to establish a committee for improving the English language came to little, the society's members did a great deal to foster the publication of science in English and to encourage the development of a suitable writing style. Many members of the Royal Society also published monographs in English. One of the first was by Robert Hooke, the society's first curator of experiments, who described his experiments with microscopes in Micrographia (1665). This work is largely narrative in style, based on a transcript of oral demonstrations and lectures.

In 1665 a new scientific journal, Philosophical Transactions, was inaugurated. Perhaps the first international English-language scientific journal, it encouraged a new genre of scientific writing, that of short, focused accounts of particular experiments.

The 17th century was thus a formative period in the establishment of scientific English. In the following century, much of this momentum was lost as German established itself as the leading European language of science. It is estimated that by the end of the 18th century 401 German scientific journals had been established as opposed to 96 in France and 50 in England. However, in the 19th century, scientific English again enjoyed substantial lexical growth as the industrial revolution created the need for new technical vocabulary, and new, specialised, professional societies were instituted to promote and publish in the new disciplines.

1. lingua franca: a language which is used for communication between groups of people who speak different languages

Questions 28-34
Complete the summary. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 28-34 on your answer sheet.

In Europe, modern science emerged at the same time as the nation state. At first, the scientific language of choice remained 28 ............. It allowed scientists to communicate with other socially privileged thinkers while protecting their work from unwanted exploitation. Sometimes the desire to protect ideas seems to have been stronger than the desire to communicate them, particularly in the case of mathematicians and 29 ................. In Britain, moreover, scientists worried that English had neither the 30 ......................... nor the 31 ................ to express their ideas.This situation only changed after 1660 when scientists associated with the 32 ................. set about developing English. An early scientific journal fostered a new kind of writing based on short descriptions of specific experiments. Although English was then overtaken by 33 ......................... it developed again in the 19th century. as a direct result of the 34 ..........................

Questions 35-37
Do the following statements agree with the information given in Reading Passage 3? In boxes 35-37 on your answer sheet, write:

YES if the statement agrees with the writer's claims
NO if the statement contradicts the writer's claims
NOT GIVEN if it is impossible to say what the writer thinks about this

35. There was strong competition between scientists in Renaissance Europe.
36. The most important scientific development of the Renaissance period was the discovery of magnetism.
37. In 17th-century Britain, leading thinkers combined their interest in science with an interest in how to express ideas.

Questions 38-40
Complete the table. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 38-40 on your answer sheet.

The Birth of Scentific English

17. Bài 17

The Return of Artificial Intelligence

It is becoming acceptable again to talk of computers performing human tasks such as problem-solving and pattern-recognition.

A. After years in the wilderness, the term 'artificial intelligence' (AI) seems poised to make a comeback. AI was big in the 1980s but vanished in the 1990s. It re-entered public consciousness with the release of Al, a movie about a robot boy. This has ignited a public debate about AI, but the term is also being used once more within the computer industry. Researchers, executives and marketing people are now using the expression without irony or inverted commas. And it is not always hype. The term is being applied, with some justification, to products that depend on technology that was originally developed by AI researchers. Admittedly, the rehabilitation of the term has a long way to go, and some firms still prefer to avoid using it. But the fact that others are starting to use it again suggests that AI has moved on from being seen as an over-ambitious and under-achieving field of research.

B. The field was launched, and the term 'artificial intelligence' coined, at a conference in 1956 by a group of researchers that included Marvin Minsky, John McCarthy, Herbert Simon and Alan Newell, all of whom went on to become leading figures in the field. The expression provided an attractive but informative name for a research programme that encompassed such previously disparate fields as operations research, cybernetics, logic and computer science. The goal they shared was an attempt to capture or mimic human abilities using machines. That said, different groups of researchers attacked different problems, from speech recognition to chess playing, in different ways; AI unified the field in name only. But it was a term that captured the public imagination.

C. Most researchers agree that AI peaked around 1985. A public reared on science-fiction movies and excited by the growing power of computers had high expectations. For years, AI researchers had implied that a breakthrough was just around the corner. Marvin Minsky said in 1967 that within a generation the problem of creating'artificial intelligence' would be substantially solved. Prototypes of medical-diagnosis programs and speech recognition software appeared to be making progress. It proved to be a false dawn. Thinking computers and household robots failed to materialise, and a backlash ensued. `There was undue optimism in the early 1980s; says David Leaky, a researcher at Indiana University. 'Then when people realised these were hard problems, there was retrenchment. By the late 1980s, the term AI was being avoided by many researchers, who opted instead to align themselves with specific sub-disciplines such as neural networks, agent technology, case-based reasoning, and so on.

D. Ironically, in some ways AI was a victim of its own success. Whenever an apparently mundane problem was solved, such as building a system that could land an aircraft unattended, the problem was deemed not to have been AI in the first plate. 'If it works, it can't be AI; as Dr Leaky characterises it. The effect of repeatedly moving the goal-posts in this way was that AI came to refer to 'blue-sky' research that was still years away from commercialisation. Researchers joked that AI stood for `almost implemented'. Meanwhile, the technologies that made it onto the market, such as speech recognition, language translation and decision-support software, were no longer regarded as AI. Yet all three once fell well within the umbrella of AI research.

E. But the tide may now be turning, according to Dr Leake. HNC Software of San Diego, backed by a government agency, reckon that their new approach to artificial intelligence is the most powerful and promising approach ever discovered. HNC claim that their system, based on a cluster of 30 processors, could be used to spot camouflaged vehicles on a battlefield or extract a voice signal from a noisy background - tasks humans can do well, but computers cannot. 'Whether or not their technology lives up to the claims made for it, the fact that HNC are emphasising the use of AI is itself an interesting development; says Dr Leaky.

F. Another factor that may boost the prospects for AI in the near future is that investors are now looking for firms using clever technology, rather than just a clever business model, to differentiate themselves. In particular, the problem of information overload, exacerbated by the growth of e-mail and the explosion in the number of web pages, means there are plenty of opportunities for new technologies to help filter and categorise information - classic AI problems. That may mean that more artificial intelligence companies will start to emerge to meet this challenge.

G. The 1969 film, 2001: A Space Odyssey, featured an intelligent computer called HAL 9000. As well as understanding and speaking English, HAL could play chess and even learned to lipread. HAL thus encapsulated the optimism of the 1960s that intelligent computers would be widespread by 2001. But 2001 has been and gone, and there is still no sign of a HAL-like computer. Individual systems can play chess or transcribe speech, but a general theory of machine intelligence still remains elusive. It may be, however, that the comparison with HAL no longer seems quite so important, and AI can now be judged by what it can do, rather than by how well it matches up to a 30-year-old science-fiction film. 'People are beginning to realise that there are impressive things that these systems can do; says Dr Leake hopefully.

Questions 27-31
Reading Passage 3 has seven paragraphs, A-G. Write the correct letter A-G in boxes 27-31 on your answer sheet.
NB. You may use any letter more than once.

Which paragraph contains the following information?

27. how AI might have a military impact
28. the fact that AI brings together a range of separate research areas
29. the reason why AI has become a common topic of conversation again

30. how AI could help deal with difficulties related to the amount of information available electronically
31. where the expression AI was first used

Questions 32-37
Do the following statements agree with the information given in Reading Passage 3? In boxes 32-37 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

32. The researchers who launched the field of AI had worked together on other projects in the past.
33. In 1985, AI was at its lowest point.
34. Research into agent technology was more costly than research into neural networks.
35. Applications of AI have already had a degree of success.
36. The problems waiting to be solved by AI have not changed since 1967.
37. The film 2001: A Space Odyssey reflected contemporary ideas about the potential of AI computers.

Questions 38-40
Choose the correct letter, A, B, C or D. Write your answers in boxes 38-40 on your answer sheet.

38. According to researchers, in the late 1980s, there was a feeling that
A. a general theory of AI would never be developed.
B. original expectations of AI may not have been justified.
C. a wide range of applications was close to fruition.
D. more powerful computers were the key to further progress.

39. In Dr Leake's opinion, the reputation of AI suffered as a result of
A. changing perceptions.
B. premature implementation.
C. poorly planned projects.
D. commercial pressures.

40. The prospects for AI may benefit from
A. existing AI applications.
B. new business models.
C. orders from Internet-only companies.
D. new investment priorities.

18. Bài 18

Flawed Beauty: the problem with toughened glass

On 2nd August 1999, a particularly hot day in the town of Cirencester in the UK, a large pane of toughened glass in the roof of a shopping centre at Bishops Walk shattered without warning and fell from its frame.

When fragments were analysed by experts at the giant glass manufacturer Pilkington, which had made the pane, they found that minute crystals of nickel sulphide trapped inside the glass had almost certainly caused the failure.

'The glass industry is aware of the issue,' says Brian Waldron, chairman of the standards committee at tine Glass and Glazing Federation, a British trade association, and standards development officer at Pilkington. But he insists that cases are few and far between. ‘It's a very rare phenomenon.' he says.

Others disagree. 'On average I see about one or two buildings a month suffering from nickel sulphide related failures,' says Barrie Josie, a consultant engineer involved in the Bishops Walk investigation. Other experts tell of similar experiences. Tony Wilmott of London based consulting engineers Sandberg, and Simon Armstrong at CladTech Associates in Hampshire both say they know of hundreds of cases. 'What you hear is only the tip of the iceberg.' says Trevor Ford, a glass expert at Resolve Engineering in Brisbane. Queensland. He believes the reason is simple: 'No-one wants bad press.'

Toughened glass is found everywhere, from cars and bus shelters to the windows, walls and roofs of thousands of buildings around the world. It's easy to see why. This glass has five times the strength of standard glass, and when it does break it shatters into tiny cubes rather than large, razor-sharp shards. Architects love it because large panels can be bolted together to make transparent walls, and turning it into ceilings and floors is almost as easy.

It is made by heating a sheet of ordinary glass to about 620°C to soften it slightly, allowing its structure to expand, and then cooling it rapidly with jets of cold air. This causes the outer layer of the pane to contract and solidify before the interior. When the interior finally solidifies and shrinks, it exerts a pull on the outer layer that leaves It in permanent compression and produces a tensile force inside the glass. As cracks propagate best in materials under tension, the compressive force on the surface must be overcome before the pane will break, making it more resistant to cracking.

The problem starts when glass contains nickel sulphide impurities. Trace amounts of nickel and sulphur are usually present in the raw materials used to make glass, and nickel can also be introduced by fragments of nickel alloys falling into the molten glass. As the glass is heated, these atoms react to form tiny crystals of nickel sulphide. Just a tenth of a gram of nickel in the furnace can create up to 50,000 crystals.

These crystals can exist in two forms: a dense form called the alpha phase, which is stable at high temperatures, and a less dense form called the beta phase, which is stable at room temperatures. The high temperatures used in the toughening process convert all the crystals to the dense, compact alpha form. But the subsequent cooling is so rapid that the crystals don't have time to change back to the beta phase. This leaves unstable alpha crystals in the glass, primed like a coiled spring, ready to revert to the beta phase without warning.

When this happens, the crystals expand by up to 4%. And if they are within the central, tensile region of the pane, the stresses this unleashes can shatter the whole sheet. The time that elapses before failure occurs is unpredictable. It could happen just months after manufacture, or decades later, although if the glass is heated - by sunlight, for example - the process is speeded up. Ironically, says Graham Dodd, of consulting engineers Arup in London, the oldest pane of toughened glass known to have failed due to nickel sulphide inclusions was in Pilkington's glass research building in Lathom, Lancashire. The pane was 27 years old.

Data showing the scale of the nickel sulphide problem is almost impossible to find. The picture is made more complicated by the fact that these crystals occur in batches. So even if, on average, there is only one inclusion in 7 tonnes of glass, if you experience one nickel sulphide failure in your building, that probably means you've got a problem in more than one pane. Josie says that in the last decade he has worked on over 15 buildings with the number of failures into double figures.

One of the worst examples of this is Waterfront Place, which was completed in 1990. Over the following decade the 40- storey Brisbane block suffered a rash of failures. Eighty panes of its toughened glass shattered due to inclusions before experts were finally called in. John Barry, an expert in nickel sulphide contamination at the University of Queensland, analysed every glass pane in the building. Using a studio camera, a photographer went up in a cradle to take photos of every pane. These were scanned under a modified microfiche reader for signs of nickel sulphide crystals. ‘We discovered at least another 120 panes with potentially dangerous inclusions which were then replaced,’ says Barry. ‘It was a very expensive and time consuming process that took around six months to complete.'

Though the project cost A$1.6 million (nearly £700,000), the alternative - re-cladding the entire building - would have cost ten times as much.

Questions 14-17
Look at the following people and the list of statements below. Match each person with the correct statement. Write the correct letter A-H in boxes 14-17 on your answer sheet.

14. Brian Waldron
15. Trevor Ford
16. Graham Dodd
17. John Barry

List of Statements

A. suggests that publicity about nickel sulphide failure has been suppressed
B. regularly sees cases of nickel sulphide failure
C. closely examined all the glass in one building
D. was involved with the construction of Bishops Walk
E. recommended the rebuilding of Waterfront Place
F. thinks the benefits of toughened glass are exaggerated
G. claims that nickel sulphide failure is very unusual
H. refers to the most extreme case of delayed failure

Questions 18-23
Complete the summary with the list of words A-P below. Write your answers in boxes 18-23 on your answer sheet.

Toughened Glass

Toughened glass is favoured by architects because it is much stronger than ordinary glass, and the fragments are not as 18 .................... when it breaks. However, it has one disadvantage: it can shatter 19 ........................ This fault is a result of the manufacturing process. Ordinary glass is first heated, then cooled very 20 ....................... .
The outer layer 21 ....................... before the inner layer and the tension between the two layers which is created because of this makes the glass stronger. However, if the glass contains nickel sulphide impurities, crystals of nickel sulphide are formed. These are unstable, and can expand suddenly, particularly if the weather is 22 ........................ If this happens, the pane of glass may break. The frequency with which such problems occur is 23 ....................... by glass experts. Furthermore, the crystals cannot be detected without sophisticated equipment.

A. numerous

B. detected

C. quickly

D. agreed
E. warm

F. sharp

G. expands

H. slowly
I. unexpectedly

J. removed

K. contracts

L. disputed
M. cold

N. moved

O. small

P. calculated

Questions 24-26
Do the following statements agree with the information given in Reading Passage 2? vIn boxes 24-26 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

24. Little doubt was expressed about the reason for the Bishops Walk accident.
25. Toughened glass has the same appearance as ordinary glass.
26. There is plenty of documented evidence available about the incidence of nickel sulphide failure.

19. Bài 19

A. The Lumière Brothers opened their Cinematographe, at 14 Boulevard des Capucines in Paris, to 100 paying customers over 100 years ago, on December 8, 1985. Before the eyes of the stunned, thrilled audience, photographs came to life and moved across a flat screen.

B. So ordinary and routine has this become to us that it takes a determined leap of imagination to grasp the impact of those first moving images. But it is worth trying, for to understand the initial shock of those images is to understand the extraordinary power and magic of cinema, the unique, hypnotic quality that has made films the most dynamic, effective art form of the 20th century.

C. One of the Lumière Borthers’ earliest films was a 30-second piece which showed a section of a railway platform flooded with sunshine. A train appears and heads straight for the camera. And that is all that happens. Yet the Russian director Andrei Tarkovsky, one of the greatest of all film artists, described the film as a ‘work of genius’. ‘As the train approached,’ wrote Tarkovsky, ’panic started in the theatre: people jumped and ran away. That was the moment when cinema was born. The frightened audience could not accept that they were watching a mere picture. Pictures were still, only reality moved; this must, therefore, be reality. In their confusion, they feared that a real train was about to crush them.’

D. Early cinema audiences often experienced the same confusion. In time, the idea of films became familiar, the magic was accepted- but it never stopped being magic. Film has never lost its unique power to embrace its audience and transport them to a different world. For Tarkovsky, the key to that magic dynamic image of the real flow of events. A still picture could only imply the existence of time, while time in a novel passed at the whim of the reader. But in cinema, the real, objective flow of time was captured.

E. One effect of this realism was to educate the world about itself. For cinema makes the world smaller. Long before people travelled to America or anywhere else, they knew what other places looked like; they knew how other people worked and lived. Overwhelmingly, the lives recorded at least in film fiction- have been American. From the earliest days of the industry, Hollywood has dominated the world film market. American imagery-the cars, the cities, the cowboys became the primary imagery of film. Film carried American life and values around the globe.

F. And, thanks to film, future generations will know the 20-th century more intimately than any other period. We can only imagine what life was like in the 14th century or in classical Rome. But the life of the modern world has been recorded on film in massive encyclopaedic detail. We shall be known better than any preceding generations.

G. The 'star' was another natural consequence of cinema. The cinema star was effectively born in 1910. Film personalities have such an immediate presence that inevitably, they become super-real. Because we watch them so closely and because everybody in the world seems to know who they are, they appear more real to us than we do ourselves. The star as magnified human self is one of cinema's most strange and enduring legacies.

H. Cinema has also given a new lease of life to the idea of the story. When the Lumiere Brothers and other pioneers began showing off this new invention, it was by no means obvious how it would be used. All that mattered at first was the wonder of movement. Indeed, some said that, once this novelty had worn off, cinema would fade away. It was no more than a passing gimmick, a fairground attraction.

I. Cinema might, for example, have become primarily a documentary form. Or it might have developed like television -as a strange noisy transfer of music, information and narrative. But what happened was that it became, overwhelmingly, a medium for telling stories. Originally these were conceived as short stories- early producers doubted the ability of audiences to concentrate for more than the length of a reel. Then, in 1912, an Italian 2-hour film was hugely successful, and Hollywood settled upon the novel-length narrative that remains the dominant cinematic convention of today.

J. And it has all happened so quickly. Almost unbelievably, it is a mere 100 years since that train arrived and the audience screamed and fled, convinced by the dangerous reality of what they saw, and, perhaps, suddenly aware that the world could never be the same again -that, maybe, it could be better, brighter, more astonishing, more real than reality.

Questions 1-5
Reading Passage 1 has ten paragraphs, A-J. Write the correct letter, A-J. in boxes 1-5 on your answer sheet.
Which paragraph contains the following information?

1. the location of [he first cinema
2. how cinema came to focus on stories
3. the speed with which cinema has changed
4. how cinema teaches us about other cultures
5. the attraction of actors in films

Questions 6-9
Do the following statements agree with the views of the writer in Reading Passage 1? In boxes 6-9 on your answer sheet, write:

YES if the statement agrees with the views of the writer
NO if the statement contradicts the views of the writer
NOT GIVEN if it is impossible to say what the writer thinks about this

6. It is important to understand how the first audiences reacted to the cinema.
7. The Lumiere Brothers' film about the train was one of the greatest films ever made.
8. Cinema presents a biased view of other countries.
9. Storylines were important in very early cinema.

Questions 10-13
Choose the correct letter. A, B, C or D. Write the correct letter in boxes 10-13 on your answer sheet.

10. The writer refers to the film of the train in order to demonstrate
A. the simplicity of early films.
B. the impact of early films.
C. how short early films were.
D. how imaginative early films were.

11. In Tarkovsky's opinion, the attraction of the cinema is that it
A. aims to impress its audience.
B. tells stories better through books.
C. illustrates the passing of lime.
D. describes familiar events.

12. When cinema first began, people thought that
A. it would always tell stories.
B. it should be used in fairgrounds.
C. US audiences were unappreciative.
D. its future was uncertain.

13. What is the best title for this passage?
A. The rise of the cinema star
B. Cinema and novels compared
C. The domination of Hollywood
D. The power of the big screen

20. Bài 20

Pulling string to build pyramids

No one knows exactly how- the pyramids were built. Marcus Chown reckons the answer could be 'hanging in the air'.

The pyramids of Egypt were built more than three thousand years ago, and no one knows how. The conventional picture is that tens of thousands of slaves dragged stones on sledges. But there is no evidence to back this up. Now a Californian software consultant called Maureen Clemmons has suggested that kites might have been involved. While perusing a book on the monuments of Egypt, she noticed a hieroglyph that showed a row of men standing in odd postures. They were holding what looked like ropes that led, via some kind of mechanical system, to a giant bird in the sky. She wondered if perhaps the bird was actually a giant kite, and the men were using it to lift a heavy object.

Intrigued, Clemmons contacted Morteza Gharib, aeronautics professor at the California Institute of Technology. He was fascinated by the idea. 'Coming from Iran, I have a keen interest in Middle Eastern science, he says. He too was puzzled by the picture that had sparked Clemmons's interest. The object in the sky apparently had wings far too short and wide for a bird 'The possibility certainly existed that it was a kite, he says. And since he needed a summer project for his student Emilio Graff, investigating the possibility of using kites as heavy lifters seemed like a good idea.

Gharib and Graff set themselves the task of raising a 4.5-metre stone column from horizontal to vertical, using no source of energy except the wind. Their initial calculations and scale-model wind-tunnel experiments convinced them they wouldn't need a strong wind to lift the 33.5-tonne column. Even a modest force, if sustained over a long lime, rose, the base would roll across the ground on a trolley.

Earlier this year, the team put Clemmons's unlikely theory to the test, using a 40-square-meter rectangular nylon sail. The kite lifted the column clean off the ground. 'We were absolutely stunned, Gharib says. The instant the sail opened into the wind, a huge force was generated and the column was raised to the vertical in a mere 40 seconds.'

The wind was blowing at a gentle 16 to 20 kilometers an hour, little more than half what they thought would be needed. What they had failed to reckon with was what happened when the kite was opened. There was a huge initial force - five times larger than the steady state force, Gharib says. This jerk meant that kites could lift huge weights, Gharib realised. Even a 300-tonne column could have been lifted to the vertical with 40 or so men and four or five sails. So Clemmons was right: the pyramid builders could have used kites to lift massive stones into place. 'Whether they actually did is another matter,' Gharib says. There are no pictures showing the construction of the pyramids, so there is no way to tell what really happened. The evidence for using kites to move large stones is no better or worse than the evidence for the brute force method, Gharib says.

Indeed, the experiments triage left many specialists unconvinced. The evidence for kite - lifting is non-existent, says Wallace Wendrich, an associate professor of Egyptology at the University of California, Los Angeles.

Other feel there is more of a case for the theory. Harnessing the wind would not have been a problem for accomplished sailors like the Egyptians. And they are known to have used wooden pulleys, which could have been made strong enough to bear the weight of massive blocks of stone. In addition, there is some physical evidence that the ancient Egyptians were interested in flight. A wooden artifact found on the step pyramid at Saqqara looks uncannily like a modern glider. Although it dates from several hundred years after the building of the pyramids, its sophistication suggests that the Egyptians might have been developing ideas of flight for a long time. And other ancient civilisations certainly knew about kites; as early as 1250 BC, the Chinese were using them to deliver messages and dump flaming debris on their foes.

The experiments might even have practical uses nowadays. There are plenty of places around the globe where people have no access to heavy machinery, but do know how to deal with, wind, sailing and basic mechanical principles. Gharib has already been contacted by a civil engineer in Nicaragua, who wants to put up buildings with adobe roofs supported by concrete arches on a site that heavy equipment can't reach. His idea is to build the arches horizontally, then lift them into place using kites. 'We've given him some design hints, says Gharib. 'We're just waiting for him to report back.' So whether they were actually used to build the pyramids or not, it seems that kites may make sensible construction tools in the 21st century AD.

Questions 1-7
Do the following statement with the information given in Reading Passage 1? In boxes 1-7 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

1. It is generally believed that large numbers of people were needed to build the pyramids.
2. Clemmons found a strange hieroglyph on the wall of an Egyptian monument.

3. Gharib had previously done experiments on bird flight.
4. Ghari band Graff tested their theory before applying it.
5. The success of the actual experiment was due to the high speed of the wind.
6. They found that, as the kite flew higher, the wind force got stronger.
7. The team decided that it was possible to use kites to raise very heavy stones.
Questions 8-13
Complete the summary below. Choose NO MORE THAN WORDS from the passage for each answer. Write your answers in boxes 8-13 your answer sheet.

Addition evidence for theory of kite lifting

The Egyptians had 8………………, which could lift large pieces of 9...................., and they knew how to use the energy of the wind from their skill as 10................... The discovery on one pyramid of an object which resembled a 11................. suggests they may have experimented with 12 .............. . In addition, over two thousand years ago kites used in China as weapons, as well as for sending 13..................

21. Bài 21

THE IRON BRIDGE

The Iron Bridge was the first of its kind in Europe and is universally recognised as a symbol of the Industrial Revolution.

A. The Iron Bridge crosses the River Severn in Coalbrookdale, in the west of England. It was the first cast-iron bridge to be successfully erected, and the first large cast-iron structure of the industrial age in Europe, although the Chinese were expert iron-casters many centuries earlier.
B. Rivers used to be the equivalent of today’s motorways, in that they were extensively used for transportation. The River Severn, which starts its life on the Welsh mountains and eventually enters the sea between Cardiff and Bristol, is the longest navigable river in Britain. It was ideal for transportation purposes, and special boats were built to navigate the waters. By the middle of the eighteenth century, the Severn was one of the busiest rivers in Europe. Local goods, including coal, iron products, wool, grain and cider, were sent by river. Among the goods coming upstream were luxuries such as sugar, tea, coffee and wine. In places, the riverbanks were lined with wharves and the river was often crowded with boats loading or unloading.
C. In 1638, Basil Brooke patented a steel-making process and built a furnace at Coalbrookdale. This later became the property of Abraham Darby (referred to as Abraham Darby I to distinguish him from his son and grandson of the same name). After serving an apprenticeship in Birmingham, Darby had started a business in Bristol, but he moved to Coalbrookdale in 1710 with an idea that coke derived from coal could provide a more economical alternative to charcoal as a fuel for iron making. This led to cheaper, more efficient iron making from the abundant supplies of coal, iron and limestone in the area.
D. His son, Abraham Darby II, pioneered the manufacture of cast iron, and had the idea of building a bridge over the Severn, as ferrying stores of all kinds across the river, particularly the large quantities of fuel for the furnaces at Coalbrookdale and other surrounding ironworks, involved considerable expense and delay. However, it was his son Abraham Darby III (born in 1750) who, in 1775, organised a meeting to plan the building of a bridge. This was designed by a local architect, Thomas Pritchard, who had the idea of constructing it of iron.
E. Sections were cast during the winter of 1778-9 for a 7-metre-wide bridge with a span of 31 metres, 12 metres above the river. Construction took three months during the summer of 1779, and remarkably, nobody was injured during the construction process – a feat almost unheard of even in modern major civil engineering projects. Work on the approach roads continued for another two years, and the bridge was opened to traffic in 1781. Abraham Darby III funded the bridge by commissioning paintings and engravings, but he lost a lot on the project, which had cost nearly double the estimate, and he died leaving massive debts in 1789, aged only 39. The district did not flourish for much longer, and during the
nineteenth and early twentieth centuries factories closed down. Since 1934 the bridge has been open only to pedestrians. Universally recognised as the symbol of the Industrial Revolution, the Iron Bridge now stands at the heart of the Iron bridge Gorge World Heritage Site.
F. It has always been a mystery how the bridge was built. Despite its pioneering technology, no eye-witness accounts are known which describe the iron bridge being erected – and certainly no plans have survived. However, recent discoveries, research and experiments have shed new light on exactly how it was built, challenging the assumptions of recent decades. In 1997 a small watercolour sketch by Elias Martin came to light in the Swedish capital, Stockholm. Although there is a wealth of early views of the bridge by numerous artists, this is the only one which actually shows it under construction.
G. Up until recently it had been assumed that the bridge had been built from both banks, with the inner supports tilted across the river. This would have allowed river traffic to continue unimpeded during construction. But the picture clearly shows sections of the bridge being raised from a barge in the river. It contradicted everything historians had assumed about the bridge, and it was even considered that the picture could have been a fake as no other had come to light. So in 2001 a half-scale model of the bridge was built, in order to see if it could have been constructed in the way depicted in the watercolour. Meanwhile, a detailed archaeological, historical and photographic survey was done by the Iron bridge Gorge Museum Trust, along with a 3D CAD (computer-aided design) model by English Heritage.
H. The results tell us a lot more about how the bridge was built. We now know that all the large castings were made individually as they are all slightly different. The bridge wasn’t welded or bolted together as metal bridges are these days. Instead it was fitted together using a complex system of joints normally used for wood – but this was the traditional way in which iron structures were joined at the time. The construction of the model proved that the painting shows a very realistic method of constructing the bridge that could work and was in all probability the method used.
I. Now only one mystery remains in the Iron Bridge story. The Swedish watercolour sketch had apparently been torn from a book which would have contained similar sketches. It had been drawn by a Swedish artist who lived in London for 12 years and travelled Britain drawing what he saw. Nobody knows what has happened to the rest of the book, but perhaps the other sketches still exist somewhere. If they are ever found they could provide further valuable evidence of how the Iron Bridge was constructed.

Question 28-31
Answer the questions below. Choose ONE NUMBER ONLY from the text for each answer. Write your answers in boxes 28-31 on your answer sheet.
28. When was the furnace bought by Darby originally constructed?
29. When were the roads leading to the bridge completed?
30. When was the bridge closed to traffic?
31. When was a model of the bridge built?

Questions 32 - 36
Do the following statements agree with the information given in the text? In boxes 32 - 36 on your answer sheet, write:
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

32. There is no written evidence of how the original bridge was constructed.
33. The painting by Elias Martin is the only one of the bridge when it was new.
34. The painting shows that the bridge was constructed from the two banks.
35. The original bridge and the model took equally long to construct.
36. Elias Martin is thought to have made other paintings of the bridge.
Question 37-40
The text has nine paragraphs, A-I.
Which paragraph of the text contains the following information?

Write the correct letter A - I, in boxes 37 - 40 on your answer sheet.
37. why a bridge was required across the River Severn
38. a method used to raise money for the bridge
39. why Coalbrookdale became attractive to iron makers
40. how the sections of the bridge were connected to each other

22. Bài 22

A Chronicle of Timekeeping

Our conception of time depends on the way we measure it

A. According to archaeological evidence, at least 5, 000 years ago, and long before the advent of the Roman Empire, the Babylonians began to measure time, introducing calendars to coordinate communal activities, to plan the shipment of goods and, in particular, to regulate planting and harvesting. They based their calendars on three natural cycles: the solar day, marked by the successive periods of light and darkness as the earth rotates on its axis; the lunar month, following the phases of the moon as it orbits the earth; and the solar year, defined by the changing seasons that accompany our planet's revolution around the sun.

B. Before the invention of artificial light, the moon had greater social impact. And, for those living near the equator, in particular, its waxing and waning were more conspicuous than the passing of the seasons. Hence, the calendars that were developed at the lower latitudes were influenced more by the lunar cycle than by the solar year. In more northern climes, however, where seasonal agriculture was practised, the solar year became more crucial. As the Roman Empire expanded northward, it organised its activity chart for the most part around the solar year.

C. Centuries before the Roman Empire, the Egyptians had formulated a municipal calendar having 12 months of 30 days, with five days added to approximate the solar year. Each period of ten days was marked by the appearance of special groups of stars called decans. At the rise of the star Sirius just before sunrise, which occurred around the all-important annual flooding of the Nile, 12 decans could be seen spanning the heavens. The cosmic significance the Egyptians placed in the 12 decans led them to develop a system in which each interval of darkness (and later, each interval of daylight) was divided into a dozen equal parts. These periods became known as temporal hours because their duration varied according to the changing length of days and nights with the passing of the seasons. Summer hours were long, winter ones short; only at the spring and autumn equinoxes were the hours of daylight and darkness equal. Temporal hours, which were first adopted by the Greeks and then the Romans, who disseminated them through Europe, remained in use for more than 2, 500 years.

D. In order to track temporal hours during the day, inventors created sundials, which indicate time by the length or direction of the sun's shadow. The sundial's counterpart, the water clock, was designed to measure temporal hours at night. One of the first water clocks was a basin with a small hole near the bottom through which the water dripped out. The falling water level denoted the passing hour as it dipped below hour lines inscribed on the inner surface. Although these devices performed satisfactorily around the Mediterranean, they could not always be depended on in the cloudy and often freezing weather of northern Europe.

E. The advent of the mechanical clock meant that although it could be adjusted to maintain temporal hours, it was naturally suited to keeping equal ones. With these, however, arose the question of when to begin counting, and so, in the early 14th century, a number of systems evolved. The schemes that divided the day into 24 equal parts varied according to the start of the count: Italian hours began at sunset, Babylonian hours at sunrise, astronomical hours at midday and 'great clock' hours, used for some large public clocks in Germany, at midnight. Eventually, these were superseded by 'small clock', or French, hours, which split the day into two 12-hour periods commencing at midnight.

F. The earliest recorded weight-driven mechanical clock was built in 1283 in Bedfordshire in England. The revolutionary aspect of this new timekeeper was neither the descending weight that provided its motive force nor the gear wheels (which had been around for at least 1, 300 years) that transferred the power; it was the part called the escapement. In the early 1400s came the invention of the coiled spring or fusee which maintained a constant force to the gear wheels of the timekeeper despite the changing tension of its mainspring. By the 16th century, a pendulum clock had been devised, but the pendulum swung in a large arc and thus was not very efficient.

G. To address this, a variation on the original escapement was invented in 1670, in England. It was called the anchor escapement, which was a lever-based device shaped like a ship's anchor. The motion of a pendulum rocks this device so that it catches and then releases each tooth of the escape wheel, in turn allowing it to turn a precise amount. Unlike the original form used in early pendulum clocks, the anchor escapement permitted the pendulum to travel in a very small arc. Moreover, this invention allowed the use of a long pendulum which could beat once a second and thus led to the development of a new floor-standing case design, which became known as the grandfather clock.

H. Today, highly accurate timekeeping instruments set the beat for most electronic devices. Nearly all computers contain a quartz-crystal clock to regulate their operation. Moreover, not only do time signals beamed down from Global Positioning System satellites calibrate the functions of precision navigation equipment, they do so as well for mobile phones, instant stock-trading systems and nationwide power-distribution grids. So integral have these time-based technologies become to day-to-day existence that our dependency on them is recognised only when they fail to work.

Questions 1-4
Reading Passage 1 has eight paragraphs, A-H.
Which paragraph contains the following information?
Write the correct letter, A-H, in boxes 1- 4 on your answer sheet.
1. a description of an early timekeeping invention affected by cold temperatures
2. an explanation of the importance of geography in the development of the calendar in farming communities
3. a description of the origins of the pendulum clock
4. details of the simultaneous efforts of different societies to calculate time using uniform hours

Questions 5-8
Look at the following events (Questions 5-8) and the list of nationalities below. Match each event with the correct nationality, A-F. Write the correct letter, A-F, in boxes 5-8 on your answer sheet.

5. They devised a civil calendar in which the months were equal in length.
6. They divided the day into two equal halves.
7. They developed a new cabinet shape for a type of timekeeper.
8. They created a calendar to organise public events and work schedules.

List of Nationalities

A. Babylonians
B. Egyptians
C. Greeks
D. English
E. Germans
F. French
Questions 9-13
Label the diagram below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 9-13 in your answer sheet.

A Chronicle of Timekeeping

23. Bài 23

Questions 14-19
Reading Passage 2 has seven paragraphs, A-G. Choose the correct heading for paragraphs A and C-G from the list below. Write the correct number, i-x, in boxes 14-19 on your answer sheet.

List of Headings

i. Disobeying FAA regulations

ii. Aviation disaster prompts action

iii. Two coincidental developments

iv. Setting altitude zones

v. An oversimplified view

vi. Controlling pilots’ licences

vii. Defining airspace categories

viii. Setting rules to weather conditions

ix. Taking off safely

x. First steps towards ATC

14. Paragraph A

Example: Paragraph B. Answer: x

15. Paragraph C

16. Paragraph D

17. Paragraph E

18. Paragraph F

19. Paragraph G

Air Traffic Control in the USA

A. An accident that occurred in the skies over the Grand Canyon in 1956 resulted in the establishment of the Federal Aviation Administration (FAA) to regulate and oversee the operation of aircraft in the skies over the United States, which were becoming quite congested. The resulting structure of air traffic control has greatly increased the safety of flight in the United States, and similar air traffic control procedures are also in place over much of the rest of the world.

B. Rudimentary air traffic control (АТС) existed well before the Grand Canyon disaster. As early as the 1920s, the earliest air traffic controllers manually guided aircraft in the vicinity of the airports, using lights and flags, while beacons and flashing lights were placed along cross-country routes to establish the earliest airways. However, this purely visual system was useless in bad weather, and, by the 1930s, radio communication was coming into use for АТС. The first region to have something approximating today's АТС was New York City, with other major metropolitan areas following soon after.
C. In the 1940s, АТС centres could and did take advantage of the newly developed radar and improved radio communication brought about by the Second World War, but the system remained rudimentary. It was only after the creation of the FAA that full-scale regulation of America's airspace took place, and this was fortuitous, for the advent of the jet engine suddenly resulted in a large number of very fast planes, reducing pilots' margin of error and practically demanding some set of rules to keep everyone well separated and operating safely in the air.

D. Many people think that АТС consists of a row of controllers sitting in front of their radar screens at the nation's airports, telling arriving and departing traffic what to do. This is a very incomplete part of the picture. The FAA realised that the airspace over the United States would at any time have many different kinds of planes, flying for many different purposes, in a variety of weather conditions, and the same kind of structure was needed to accommodate all of them.

E. To meet this challenge, the following elements were put into effect. First, АТС extends over virtually the entire United States. In general, from 365m above the ground and higher, the entire country is blanketed by controlled airspace. In certain areas, mainly near airports, controlled airspace extends down to 215m above the ground, and, in the immediate vicinity of an airport, all the way down to the surface. Controlled airspace is that airspace in which FAA regulations apply. Elsewhere, in uncontrolled airspace, pilots are bound by fewer regulations. In this way, the recreational pilot who simply wishes to go flying for a while without all the restrictions imposed by the FAA has only to stay in uncontrolled airspace, below 365m, while the pilot who does want the protection afforded by АТС can easily enter the controlled airspace.
F. The FAA then recognised two types of operating environments. In good meteorological conditions, flying would be permitted under Visual Flight Rules (VFR), which suggests a strong reliance on visual cues to maintain an acceptable level of safety. Poor visibility necessitated a set of Instrumental Flight Rules (IFR), under which the pilot relied on altitude and navigational information provided by the plane's instrument panel to fly safely. On a clear day, a pilot in controlled airspace can choose a VFR or IFR flight plan, and the FAA regulations were devised in a way which accommodates both VFR and IFR operations in the same airspace. However, a pilot can only choose to fly IFR if they possess an instrument rating which is above and beyond the basic pilot's license that must also be held.

G. Controlled airspace is divided into several different types, designated by letters of the alphabet. Uncontrolled airspace is designated Class F, while controlled airspace below 5,490m above sea level and not in the vicinity of an airport is Class E. All airspace above 5,490m is designated Class A. The reason for the division of Class E and Class A airspace stems from the type of planes operating in them. Generally, Class E airspace is where one finds general aviation aircraft (few of which can climb above 5,490m anyway), and commercial turboprop aircraft. Above 5,490m is the realm of the heavy jets, since jet engines operate more efficiently at higher altitudes. The difference between Class E and A airspace is that in Class A, all operations are IFR, and pilots must be instrument-rated, that is, skilled and licensed in aircraft instrumentation. This is because АТС control of the entire space is essential. Three other types of airspace, Classes D, С and B, govern the vicinity of airports. These correspond roughly to small municipal, medium-sized metropolitan and major metropolitan airports respectively, and encompass an increasingly rigorous set of regulations. For example, all a VFR pilot has to do to enter Class С airspace is establish two-way radio contact with АТС. No explicit permission from АТС to enter is needed, although the pilot must continue to obey all regulations governing VFR flight. To enter Class В airspace, such as on approach to a major metropolitan airport, an explicit АТС clearance is required. The private pilot who cruises without permission into this airspace risks losing their license.

Question 20-26
Do the following statements agrees with the given information of the reading passage 2? In boxes 20-26 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

20. The FAA was created as a result of the introduction of the jet engine.
21. Air traffic control started after the Grand Canyon crash in 19 56.
22. Beacons and flashing lights are still used by the ATC today.
23. Some improvements were made in radio communication during World War II.
24. Class F airspace is airspace which is below 365m and not near airports.
25. All aircraft in class E airspace must use AFR.
26. A pilot entering class C airspace is flying over an average-sized city.

24. Bài 24

Sheet glass manufacture: the float process

Glass, which has been made since the time of the Mesopotamians and Egyptians, is little more than a mixture of sand, soda ash and lime. When heated to about 1500 degrees Celsius (°C) this becomes a molten mass that hardens when slowly cooled. The first successful method for making clear and flat glass involved spinning. This method was very effective as the glass had not touched any surfaces between being soft and becoming hard, so it stayed perfectly unblemished, with a 'fire finish'. However, the process took a long time and was labour intensive.

Nevertheless, demand for flat glass was very high and glassmakers across the world were looking for a method of making it continuously. The first continuous ribbon process involved squeezing molten glass through two hot rollers, similar to an old mangle. This allowed glass of virtually any thickness to be made non-stop, but the rollers would leave both sides of the glass marked, and these would then need to be ground and polished. This part of the process rubbed away around 20 per cent of the glass, and the machines were very expensive.

The float process for making flat glass was invented by Alistair Pilkington. This process allows the manufacture of clear, tinted and coated glass for buildings, and clear and tinted glass for vehicles. Pilkington had been experimenting with improving the melting process, and in 1952 he had the idea of using a bed of molten metal to form the flat glass, eliminating altogether the need for rollers within the float bath. The metal had to melt at a temperature less than the hardening point of glass (about 600°C), but could not boil at a temperature below the temperature of the molten glass (about 1500°C). The best metal for the job was tin.

The rest of the concept relied on gravity, which guaranteed that the surface of the molten metal was perfectly flat and horizontal. Consequently, when pouring molten glass onto the molten tin, the underside of the glass would also be perfectly flat. If the glass were kept hot enough, it would flow over the molten tin until the top surface was also flat, horizontal and perfectly parallel to the bottom surface. Once the glass cooled to 604°C or less it was too hard to mark and could be transported out of the cooling zone by rollers. The glass settled to a thickness of six millimetres because of surface tension interactions between the glass and the tin. By fortunate coincidence, 60 per cent of the flat glass market at that time was for six millimetre glass.

Pilkington built a pilot plant in 1953 and by 1955 he had convinced his company to build a full-scale plant. However, it took 14 months of non-stop production, costing the company £100,000 a month, before the plant produced any usable glass. Furthermore, once they succeeded in making marketable flat glass, the machine was turned off for a service to prepare it for years of continuous production. When it started up again it took another four months to get the process right again. They finally succeeded in 1959 and there are now float plants all over the world, with each able to produce around 1000 tons of glass every day, non-stop for around 15 years.

Float plants today make glass of near optical quality. Several processes — melting, refining, homogenising — take place simultaneously in the 2000 tonnes of molten glass in the furnace. They occur in separate zones in a complex glass flow driven by high temperatures. It adds up to a continuous melting process, lasting as long as 50 hours, that delivers glass smoothly and continuously to the float bath, and from there to a coating zone and finally a heat treatment zone, where stresses formed during cooling are relieved.

The principle of float glass is unchanged since the 1950s. However, the product has changed dramatically, from a single thickness of 6.8 mm to a range from sub-millimetre to 25 mm, from a ribbon frequently marred by inclusions and bubbles to almost optical perfection. To ensure the highest quality, inspection takes place at every stage. Occasionally, a bubble is not removed during refining, a sand grain refuses to melt, a tremor in the tin puts ripples into the glass ribbon. Automated on-line inspection does two things. Firstly, it reveals process faults upstream that can be corrected. Inspection-technology allows more than 100 million measurements a second to be made across the ribbon, locating flaws the unaided eye would be unable to see. Secondly, it enables computers downstream to steer cutters around flaws.

Float glass is sold by the square metre, and at the final stage computers translate customer requirements into patterns of cuts designed to minimise waste.

Questions 1-8
Complete the table and diagram below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 1-8 on your answer sheet.

Sheet glass manufacture: the float process

Questions 9-13
Do the following statements agree with the information given in Reading Passage 1? In boxes 9-13 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

9. The metal used in the float process had to have specific properties.
10. Pilkington invested some of his own money in his float plant.
11. Pilkington's first full-scale plant was an instant commercial success.
12. The process invented by Pilkington has now been improved.
13. Computers are better than humans at detecting faults in glass.

25. Bài 25

Striking Back at Lightning With Lasers

Seldom is the weather more dramatic than when thunderstorms strike. Their electrical fury inflicts death or serious injury on around 500 people each year in the United States alone. As the clouds roll in, a leisurely round of golf can become a terrifying dice with death - out in the open, a lone golfer maybe a lightning bolt's most inviting target. And there is damage to property too. Lightning damage costs American power companies more than $100 million a year.

But researchers in the United States and Japan are planning to hit back. Already in laboratory trials they have tested strategies for neutralising the power of thunderstorms, and this winter they will brave real storms, equipped with an armoury of lasers that they will be pointing towards the heavens to discharge thunderclouds before lightning can strike.

The idea of forcing storm clouds to discharge their lightning on command is not new. In the early 1960s, researchers tried firing rockets trailing wires into thunderclouds to set up an easy discharge path for the huge electric charges that these clouds generate. The technique survives to this day at a test site in Florida run by the University of Florida, with support from the Electrical Power Research Institute (EPRI), based in California. EPRI, which is funded by power companies, is looking at ways to protect the United States' power grid from lightning strikes. 'We can cause the lightning to strike where we want it to using rockets': says Ralph Bernstein, manager of lightning projects at EPRI. The rocket site is providing precise measurements of lightning voltages and allowing engineers to check how electrical equipment bears up.

Bad behaviour
But while rockets are fine for research, they cannot provide the protection from lightning strikes that everyone is looking for. The rockets cost around $1,200 each, can only be fired at a limited frequency and their failure rate is about 40 per cent. And even when they do trigger lightning, things still do not always go according to plan. 'Lightning is not perfectly well behaved: says Bernstein. 'Occasionally, it will take a branch and go someplace it wasn't supposed to go.'

And anyway, who would want to fire streams of rockets in a populated area? 'What goes up must come down,' points out Jean-Claude Diels of the University of New Mexico. Diets is leading a project, which is backed by EPRI, to try to use lasers to discharge lightning safely — and safety is a basic requirement since no one wants to put themselves or their expensive equipment at risk. With around $500,000 invested so far, a promising system is just emerging from the laboratory.

The idea began some 20 years ago, when high-powered lasers were revealing their ability to extract electrons out of atoms and create ions. If a laser could generate a line of ionisation in the air all the way up to a storm cloud, this conducting path could be used to guide lightning to Earth, before the electric field becomes strong enough to break down the air in an uncontrollable surge. To stop the laser itself being struck, it would not be pointed straight at the clouds. Instead, it would be directed at a mirror, and from there into the sky. The mirror would be protected by placing lightning conductors dose by. Ideally, the cloud-zapper (gun) would be cheap enough to be installed around all key power installations, and portable enough to be taken to international sporting events to beam up at brewing storm clouds.

A stumbling block
However, there is still a big stumbling block. The laser is no nifty portable: it's a monster that takes up a whole room. Diels is trying to cut down the size and says that a laser around the size of a small table is in the offing. He plans to test this more manageable system on live thunderclouds next summer.

Bernstein says that Diels's system is attracting lots of interest from the power companies. But they have not yet come up with the $5 million that EPRI says will be needed to develop a commercial system, by making the lasers yet smaller and cheaper. `I cannot say I have money yet, but I'm working on it,' says Bernstein. He reckons that the forthcoming field tests will be the turning point — and he's hoping for good news. Bernstein predicts `an avalanche of interest and support' if all goes well. He expects to see loud-zappers eventually costing $50,000 to $100,000 each.

Other scientists could also benefit. With a lightning `switch' at their fingertips, materials scientists could find out what happens when mighty currents meet matter. Diels also hopes to see the birth of `interactive meteorology' — not just forecasting the weather but controlling it. `If we could discharge clouds, we might affect the weather,' he says.
And perhaps, says Diels, we'll be able to confront some other meteorological menaces. `We think we could prevent hail by inducing lightning,' he says. Thunder, the shock wave that comes from a lightning flash, is thought to be the trigger for the torrential rain that is typical of storms. A laser thunder factory could shake the moisture out of clouds, perhaps preventing the formation of the giant hailstones that threaten crops. With luck, as the storm clouds gather this winter, laser-toting researchers could, for the first time, strike back.

Questions 1-3
Choose the correct letter, A, B, C or D. Write the correct letter in boxes 1-3 on your answer sheet.

1. The main topic discussed in the text is
A. the damage caused to US golf courses and golf players by lightning strikes.
B. the effect of lightning on power supplies in the US and in Japan.

C. a variety of methods used in trying to control lightning strikes.
D. a laser technique used in trying to control lightning strikes.

2. According to the text, every year lightning
A. does considerable damage to buildings during thunderstorms.
B. kills or injures mainly golfers in the United States.
C. kills or injures around 500 people throughout the world.
D. damages more than 100 American power companies.

3. Researchers at the University of Florida and at the University of New Mexico
A. receive funds from the same source.
B. are using the same techniques.
C. are employed by commercial companies.
D. are in opposition to each other.

Questions 4-6
Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 4-6 on your answer sheet.

4. EPRI receives financial support from ...............................
5. The advantage of the technique being developed by Diets is that it can be used .............................
6. The main difficulty associated with using the laser equipment is related to its .................................

Questions 7-10
Complete the summary using the list of words, A-I, below. Write the correct letter, A-I, in boxes 7-10 on your answer sheet.

In this method, a laser is used to create a line of ionisation by removing electrons from 7 ................... This laser is then directed at 8 ....................... in order to control electrical charges, a method which is less dangerous than using 9 ....................... As a protection for the lasers, the beams are aimed firstly at 10 .......................

A. cloud-zappers

B. atoms

C. storm clouds
D. mirrors

E. technique

F. ions
G. rockets

H. conductors

I. thunder

Questions 11-13
Do the following statements agree with the information given in Reading Passage 1? In boxes 11-13 on your answer sheet write:

YES if the statement agrees with the claims of the writer
NO if the statement contradicts the claims of the writer
NOT GIVEN if it is impossible to say what the writer thinks about this

11. Power companies have given Diels enough money to develop his laser.
12. Obtaining money to improve the lasers will depend on tests in real storms.
13. Weather forecasters are intensely interested in Diels's system.

26. Bài 26

William Henry Perkin

The man who invented synthetic dyes

William Henry Perkin was born on March 12, 1838, in London, England. As a boy, Perkin’s curiosity prompted early interests in the arts, sciences. photography, and engineering. But it was a chance stumbling upon a run-down, yet functional, laboratory in his late grandfather's home that solidified the young man`s enthusiasm for chemistry.

As a student at the City of London School, Perkin became immersed in the study of chemistry. His talent and devotion to the subject were perceived by his teacher, Thomas Hall, who encouraged him to attend a series of lectures given by the eminent scientist Michael Faraday at the Royal Institution. Those speeches tired the young chemist`s enthusiasm further, and he later went on to attend the Royal College of Chemistry, which he succeeded in entering in 1853, at the age of 15.

At the time of Perkin’s enrollment, the Royal College of Chemistry was headed by the noted German chemist August Wilhelm Hofmann. Perkin’s scientific gifts soon caught Hofmann’s attention and within two years, he became Hofmann’s youngest assistant. Not long after that, Perkin made the scientific breakthrough that would bring him both fame and fortune.

At the time, quinine was the only viable medical treatment for malaria. The drug is derived from the bark of the cinchona tree, native to South America and by 1856 demand for the drug was surpassing the available supply. Thus, when Hofmann made some passing comments about the desirability of a synthetic substitute for quinine, it was unsurprising that his star pupil was moved to take up the challenge.

During his vacation in 1856, Perkin spent his time in the laboratory on the top floor of his family's house. He was attempting to manufacture quinine from aniline, an inexpensive and readily available coal tar waste product. Despite his best efforts, however, he did not end up with quinine. Instead, he produced a mysterious dark sludge. Luckily, Perkins scientific training and nature prompted him to investigate the substance further. Incorporating potassium dichromate and alcohol into the aniline at various stages of the experimental process, he finally produced a deep purple solution. And, proving the truth of the famous scientist Louis Pasteur's words 'chance favors only the prepared mind'. Perkin saw the potential of his unexpected find.

Historically, textile dyes were made from such natural sources as plants and animal excretions. Some of these, such as the glandular mucus of snails, were difficult to obtain and outrageously expensive. Indeed, the purple colour extracted from a snail was once so costly that in society at the time only the rich could afford it. Further, natural dyes tended to be muddy in hue and fade quickly. It was against this backdrop that Perkin‘s discovery was made.

Perkin quickly grasped that his purple solution could be used to colour fabric, thus making it the world’s first synthetic dye. Realising the importance of this breakthrough, he lost no time in patenting it. But perhaps the most fascinating of all Perkin`s reactions to his find was his nearly instant recognition that the new dye had commercial possibilities.

Perkin originally named his dye Tyrian Purple, but it later became commonly known as mauve (from the French for the plant used to make the colour violet). He asked advice of Scottish dye works owner Robert Pullar, who assured him that manufacturing the dye would be well worth it if the colour remained fast (i.e. would not fade) and the cost was relatively low. So, over the fierce objections of his mentor Hofmann, he left college to give birth to the modern chemical industry.

With the help of his father and brother, Perkin set up a factory not far from London. Utilizing the cheap and plentiful coal tar that was an almost unlimited byproduct of London's gas street lighting, the dye works began producing the world’s first synthetically dyed material in 1857. The company received a commercial boost from the Empress Eugenio of France, when she decided the new color flattered her. Very soon, mauve was the necessary shade for all the fashionable ladies in that country. Not to be outdone, England`s Queen Victoria also appeared in public wearing a mauve gown, thus making it all the rage in England as well. The dye was bold and fast, and the public clamoured for more. Perkin went back to the drawing board.

Although Perkins fame was achieved and fortune assured by his first discovery, the chemist continued his research. Among other dyes he developed and introduced were aniline red (1859) and aniline black (1863) and in the late 1860s, Perkin's green. It is important to note that Perkin's synthetic dye discoveries had outcomes far beyond the merely decorative. The dyes also became vital to medical research in many ways. For instance, they were used to stain previously invisible microbes and bacteria, allowing researchers to identify such bacilli as tuberculosis. cholera, and anthrax. Artificial dyes continue to play a crucial role today. And, in what would have been particularly pleasing to Perkin, their current use is in the search for a vaccine against malaria.

Question 1-7
Do the following statements agree with the information given in Reading Passage 1? In boxes 1-7 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this more than once.

1. Michael Faraday was the first person to recognize Perkin's ability as a student of chemistry.
2. Michael Faraday suggested Perkin should enroll in the Royal College of Chemistry.
3. Perkin employed August Wilhelm Hofmann as his assistant.
4. Perkin was still young when he made the discovery that made him rich and famous.
5. The trees from which quinine is derived grow only in South America.
6. Perkin hoped to manufacture a drug from a coal tar waste product.
7. Perkin was inspired by the discoveries of the famous scientist Louis Pasteur.

Question 8-13
Answer the questions below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 8-13 on your answer sheet.

8. Before Perkin’s discovery, with what group in society was the colour purple associated?
9. What potential did Perkin immediately understand that his new dye had?
10. What was the name finally used to refer to the first color Perkin invented?
11. What was the name of the person Perkin consulted before setting up his own dye works?
12. In what country did Perkins newly invented colour first become fashionable?
13. According to the passage, which disease is now being targeted by researchers using synthetic dyes?

27. Bài 27

Questions 14—17
Reading Passage 2 has five paragraphs, A-E. Choose the correct heading for paragraphs B-E from the headings below.

Write the correct number, i-vii, in boxes 14-17 on your answer sheet.

List of Headings
I. Seeking the transmission of radio signals from planets
II. Appropriate responses to signals from other civilizations
III. Vast distances to Earth’s closest neighbors
IV. Assumptions underlying the search for extra-terrestrial intelligence
V. Reasons for the search for extra-terrestrial intelligence
VI. Knowledge of extra-terrestrial life forms
VII. Likelihood of life on other planets

Example: Paragraph A. Answer: v

14. Paragraph B
15. Paragraph C
16. Paragraph D
17. Paragraph E

Is There Anybody Out There?

The Search for Extra-Terrestrial Intelligence

The question of whether we are alone in the Universe has haunted humanity for centuries, but we may now stand poised on the brink of the answer to that question, as we search for radio signals from other intelligent civilizations. This search is often known by the acronym SETI [search for extraterrestrial intelligence], is a difficult one. Although groups around the world have been searching intermittently for three decades, it is only now that we have reached the level of technology where we can make a determined attempt to search all nearby stars for any sign of life.

A. The primary reason for the search is basic curiosity - the same curiosity about the natural world that drives all pure science. We want to know whether we are alone in the Universe. We want to know whether life evolves naturally if given the right conditions, or whether there is something very special about the Earth to have fostered the variety of life forms that we see around us on the planet. The simple detection of a radio signal will be sufficient to answer this most basic of all questions. In this sense, SETI is another cog in the machinery of pure science which is continually pushing out the horizon of our knowledge. However, there are other reasons for being interested in whether life exists elsewhere. For example, we have had civilization on Earth for perhaps only a few thousand years, and the threats of nuclear war and pollution over the last few decades have told us that our survival may be tenuous. Will we last another two thousand years or will we wipe ourselves out? Since the lifetime of a planet like ours is several billion years, we can expect that if other civilizations do survive in our galaxy, their ages will range from zero to several billion years. Thus any other civilization that we hear from is likely to be far older on average than ourselves. The mere existence of such a civilization will tell of that long-term survival is possible, and gives us some cause for optimism. It is even possible that the older civilization may pass on the benefits of their experience in dealing with threats to survival such as nuclear war and global pollution, and other threats that we haven't yet discovered.

B. In discussing whether we are alone, most SETI scientists adopt two ground rules. First. UFOs [Unidentified Flying objects] are generally ignored since most scientists don`t consider the evidence for them to be strong enough to bear serious consideration (although it is also important to keep an open mind in case any really convincing evidence emerges in the future). Second, we make a very conservative assumption that we are looking for a life form that is pretty well like us, since if it differs radically from us we may well not recognize it as a life form, quite apart from whatever we are able to communicate with it. In other words, the life form we are looking for may well have two green heads and seven fingers, but it will nevertheless resemble us in that it should communicate with its fellows. Be interested in the Universe, Live on a planet orbiting a star like our Sun, and perhaps most restrictively have chemistry, like us, based on carbon and water.

C. Even when we make these assumptions. our understanding of other life forms is still severely limited. We do not even know. for example, how many stars have planets, and we certainly do not know how likely it is that life will arise naturally, given the right conditions. However, when we look at the 100 billion stars in our galaxy [the Milky Way], and 100 billion galaxies. In the observable Universe, It seems inconceivable that at least one of these planets does not have a life form on it; in fact, the best educated guess we can make using the little that we do know about the conditions for carbon-based life, leads us to estimate that perhaps one in 100,000 stars might have a life-bearing planet orbiting it. That means that our nearest neighbors are perhaps 1000 light years away. which is almost next door in astronomical terms.

D. An alien civilization could choose many different ways of sending information across the galaxy, but many of these either require too much energy. or else are severely attenuated while traversing the vast distances across the galaxy. It bums out that. for a given amount of transmitted power: radio waves in the frequency range 1000 to 3000 MHz travel the greatest distance. and so all searches to date have concentrated on looking for radio waves in this frequency range. So far there have been a number of searches by various groups around the world, including Australian searches using the radio telescope at Parkes, New South Wales. Until now there have not been any detections from the few hundred stars which have been searched. The scale of the searches has been increased dramatically since 1992, when the US Congress voted NASA $10 million per year for ten years to conduct a thorough search for extra-terrestrial life. Much of the money in this project is being spent on developing the special hardware needed to search many frequencies at once. The project has two parts. One part is a targeted search using the world's largest radio telescopes. The American-operated telescope in Arecibo. Puerto Rico and the French telescope in Nancy in France. This part of the project is searching the nearest 1000 likely stars with a high sensibility for signals in the frequency range 1000 to 3000 MHz. The other parts of the project is an undirected search which is monitoring all of the space with a lower using the smaller antennas of NASA`s Deep Space Network.
E. There is considerable debate over how we should react if we detect a signal from an alien civilization. Everybody agrees that we should not reply immediately. Quite apart from the impracticality of sending e reply over such large distances at short notice, it raises a host of ethical questions that would have to be addressed by the global community before any reply could be sent. Would the human race face the culture shock if faced with a superior and much older civilization? Luckily, there is no urgency about this. The stars being searched are hundreds of light years away. so it takes hundreds of years for their signal to reach us, and a further few hundred years for our reply to reach them. It is not important, then, if there`s a delay of a few years, or decades, while the human race debates the question of whether to reply and perhaps carefully drafts a reply.

Question 18-20
Answer the questions below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 18-20 on your answer sheet.

18. What is the life expectancy of Earth?
19. What kind of signals from other intelligent civilizations are SETI scientists searching for?
20. How many stars are the world’s most powerful radio telescopes searching?

Questions 21-26
Do the following statements agree with the views of the writer in Reading Passage 2? In boxes 21-26 on your answer sheet, write:

TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this more than once.

21. Alien civilizations may be able to help the human race to overcome serious problems
23. SETI scientists are trying to find a life form that resembles humans in many ways.
23. The Americans and Australians have co-operated on joint research projects.
24. So far SETI scientists have picked up radio signals from several stars.
25. The NASA project attracted criticism from some members of Congress.
26. If a signal from outer space is received, it will be important to respond promptly.

28. Bài 28

Venus in Transit

June 2004 saw the first passage, known as a ‘transit’, of the planet Venus across the face of the Sun in 122 years. Transits have helped shape our view of the whole Universe, as Heather Cooper and Nigel Henbest explain.

A. On 8 June 2004, more than half the population of the world were treated to a rare astronomical event. For over six hours, the planet Venus steadily inched its way over the surface of the Sun. This ‘transit’ of Venus was the first since 6 December 1882. On that occasion, the American astronomer Professor Simon Newcomb led a party to South Africa to observe the event. They were based at a girls’ school, where - it is alleged - the combined forces of three schoolmistresses outperformed the professionals with the accuracy of their observations.

B. For centuries, transits of Venus have drawn explorers and astronomers alike to the four corners of the globe. And you can put it all down to the extraordinary polymath Edmond Halley. In November 1677, Halley observed a transit of the innermost planet, Mercury, from the desolate island of St Helena in the South Pacific. He realised that, from different latitudes, the passage of the planet across the Sun’s disc would appear to differ. By timing the transit from two widely-separated locations, teams of astronomers could calculate the parallax angle - the apparent difference in position of an astronomical body due to a difference in the observer’s position. Calculating this angle would allow astronomers to measure what was then the ultimate goal: the distance of the Earth from the Sun. This distance is known as the astronomical unit’ or AU.

C. Halley was aware that the AU was one of the most fundamental of all astronomical measurements. Johannes Kepler, in the early 17th century, had shown that the distances of the planets from the Sun governed their orbital speeds, which were easily measurable. But no-one had found a way to calculate accurate distances to the planets from the Earth. The goal was to measure the AU; then, knowing the orbital speeds of all the other planets round the Sun, the scale of the Solar System would fall into place. However, Halley realised that Mercury was so far away that its parallax angle would be very difficult to determine. As Venus was closer to the Earth, its parallax angle would be larger, and Halley worked out that by using Venus it would be possible to measure the Suns distance to 1 part in 500. But there was a problem: transits of Venus, unlike those of Mercury, are rare, occurring in pairs roughly eight years apart every hundred or so years. Nevertheless, he accurately predicted that Venus would cross the face of the Sun in both 1761 and 1769 - though he didn’t survive to see either.

D. Inspired by Halley’s suggestion of a way to pin down the scale of the Solar System, teams of British and French astronomers set out on expeditions to places as diverse as India and Siberia. But things weren’t helped by Britain and France being at war. The person who deserves most sympathy is the French astronomer Guillaume Le Gentil.

He was thwarted by the fact that the British were besieging his observation site at Pondicherry in India. Fleeing on a French warship crossing the Indian Ocean, Le Gentil saw a wonderful transit - but the ship’s pitching and rolling ruled out any attempt at making accurate observations. Undaunted, he remained south of the equator, keeping himself busy by studying the islands of Mauritius and Madagascar before setting off to observe the next transit in the Philippines. Ironically after travelling nearly 50,000 kilometres, his view was clouded out at the last moment, a very dispiriting experience.

E. While the early transit timings were as precise as instruments would allow, the measurements were dogged by the ‘black drop’ effect. When Venus begins to cross the Sun’s disc, it looks smeared not circular - which makes it difficult to establish timings. This is due to diffraction of light. The second problem is that Venus exhibits a halo of light when it is seen just outside the Sun’s disc. While this showed astronomers that Venus was surrounded by a thick layer of gases refracting sunlight around it, both effects made it impossible to obtain accurate timings.

F. But astronomers laboured hard to analyse the results of these expeditions to observe Venus transits. Johann Franz Encke, Director of the Berlin Observatory, finally determined a value for the AU based on all these parallax measurements: 153,340,000 km. Reasonably accurate for the time, that is quite close to today’s value of 149,597,870 km, determined by radar, which has now superseded transits and all other methods in accuracy. The AU is a cosmic measuring rod, and the basis of how we scale the Universe today. The parallax principle can be extended to measure the distances to the stars. If we look at a star in January - when Earth is at one point in its orbit - it will seem to be in a different position from where it appears six months later. Knowing the width of Earth’s orbit, the parallax shift lets astronomers calculate the distance.

G. June 2004’s transit of Venus was thus more of an astronomical spectacle than a scientifically important event. But such transits have paved the way for what might prove to be one of the most vital breakthroughs in the cosmos - detecting Earth-sized planets orbiting other stars.

Questions 14-17
Reading Passage 2 has seven paragraphs, A-G.
Which paragraph contains the following information?
Write the correct letter A-G, in boxes 14-17 on your answer sheet.

14. examples of different ways in which the parallax principle has been applied
15. a description of an event which prevented a transit observation
16. a statement about potential future discoveries leading on from transit observations
17. a description of physical states connected with Venus which early astronomical instruments failed to overcome

Questions 18-21
Look at the following statements (Questions 18-21) and the list of people below. Match each statement with the correct person, A, B, C or D. Write the correct letter A, B, C or D. in boxes 18-21 on your answer sheet.

18. He calculated the distance of the Sun from the Earth based on observations of Venus with a fair degree of accuracy.
19. He understood that the distance of the Sun from the Earth could be worked out by comparing observations of a transit.
20. He realized that the time taken by a planet to go round the Sun depends on its distance from the Sun.
21. He witnessed a Venus transit but was unable to make any calculations.

List of People
A. Edmond Halley
B. Johannes Kepler
C. Guillaume Le Gentil
D. Johann Franz Encke

Questions 22-26
Do the following statements agree with the information given in Reading Passage 2? Write answers in boxes 22-26 on your answer sheet, write:

TRUE it the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

22. Halley observed one transit of the planet Venus.
23. Le Gentil managed to observe a second Venus transit.
24. The shape of Venus appears distorted when it starts to pass in front of the Sun.
25. Early astronomers suspected that the atmosphere on Venus was toxic.
26. The parallax principle allows astronomers to work out how far away distant stars are from the Earth.

29. Bài 29

Tidal Power

Undersea turbines which produce electricity from the tides are set to become an important source of renewable energy for Britain. It is still too early to predict the extent of the impact they may have. but all the signs are that they will play a significant role in the future.

A. Operating on the same principle as wind turbines, the power in sea turbines comes from tidal currents which turn blades similar to ships' propellers, but, unlike the wind, the tides are predictable and the power input is constant. The technology raises the prospect of Britain becoming self-sufficient in renewable energy and drastically reducing its carbon dioxide emissions, if tide, wind and wave power are all developed. Britain would be able to close gas, coal and nuclear power plants and export renewable power to other parts of Europe. Unlike wind power which Britain originally developed and then abandoned for 20 years allowing the Dutch to make it a major industry, undersea turbines could become a big export earner to island nations such as Japan and New Zealand.

B. Tidal sites have already been identified that will produce one-sixth or more of the UK’s power - and at prices competitive with modern gas turbines and undercutting those of the already ailing nuclear industry. One site alone, the Pendand Firth, between Orkney and mainland Scotland, could produce 10% of the country's electricity with banks of turbines under the sea, and another at Alderney in the Channel islands three times the 1,200 megawatts of Britain's largest and newest nuclear plant, Sizewell B, in Suffolk. Other sites identified include the Bristol Channel and the west coast of Scotland, particularly the channel between Campbeltown and Northern Ireland.

C. Work on designs for the new turbine blades and sites are well advanced at the University of Southampton‘s sustainable energy research group. The first station is expected to be installed off Lynmouth in Devon shortly to test the technology in a venture jointly funded by the department of Trade and Industry and the European Union. AbuBakr Bahaj, in charge of the Southampton research, said: The prospects for energy from tidal currents are far better than from wind because the flows of water are predictable and constant. The technology for dealing with the hostile saline environment under the sea has been developed in the North Sea oil industry and much is already known about turbine blade design, because of wind power and ship propellers. There are a few technical difficulties, but I believe in the next nine to ten years we will be installing commercial marine turbine farms.' Southampton has been awarded £2’l5.U.`D over three years to develop the turbines and is working with Marine Current Turbines. a subsidiary of IT power; on the Lynmouth project. EU research has now identified 1GB potential sites for tidal powen BG% round the coasts of Britain. The best sites are between islands or around heavily indented coasts where there are strong tidal currents.

D. A marine turbine blade needs to be only one-third of the size of a wind generator to produce three times as much power. The blades will be about 20 metres in diameter so around 30 metres of water is required. Unlike wind power, there are unlikely to be environmental objections. Fish and other creatures are thought unlikely to be at risk from the relatively slow turning blades. Each turbine will be mounted on a tower which will connect to the national power supply grid via underwater cables. The towers will stick out of the water and be lit. to warn shipping, and also be designed to be lifted out of the water for maintenance and to clean seaweed from the blades.

E. Dr Baha has done most work on the Alderrney site, where there are powerful currents. The single undersea turbine farm would produce far more power than needed for the Channel Islands and most would be fed into the French Grid and be re-imported into Britain via the cable under the Channel.

F. One technical difficulty is cavitations, where low pressure behind a turning blade causes air bubbles. These can cause vibration and damage the blades of the turbines. Dr Bahaj said: 'We have to test a number of blade types to avoid this happening or at least make sure it does not damage the turbines or reduce performance. Another slight concern is submerged debris floating into the blades. So far we do not know how much of a problem it might be. We will have to make the turbines robust because the sea is a hostile environment. but all the signs that we can do it are good.

Questions 14-17
Reading Passage 2 has six paragraphs, A-F.
Which paragraph contains the following information?
Write the correct letter; A-F in boxes 14-17 on your answer sheet.
NB You may use any letter more than once.

14. the location of the first test site
15. a way of bringing the power produced on one site back into Britain
16. a reference to a previous attempt by Britain to find an alternative source of energy
17. mention of the possibility of applying technology from another industry

Questions 18-22
Choose FIVE Letters A-J. Write the correct letters in boxes 18-22 on your answer sheet.
Which FIVE of the following claims about tidal power are made by the writer?

A. It is a more reliable source of energy than wind power.
B. It would replace all other forms of energy in Britain.
C. Its introduction has come as a result of public pressure.
D. It would cut down on air pollution.
E. It could contribute to the closure of many existing power stations ln Britain.
F. It could be a means of increasing national income.
G. It could face a lot of resistance from other fuel industries.
H. It could be sold more cheaply than any other type of fuel.
I. It could compensate for the shortage of inland sites for energy production.
J. It is best produced in the vicinity of coastlines with particular features.

Questions 23-26
Label the diagram below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 23-26 on your answer sheet.

Tidal Power

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