剑桥雅思真题3 Test1 三篇文章(9页).doc
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1、-剑桥雅思真题3 Test1 三篇文章-第 9 页C3 TEST 1 PASSAGE 1:The rocket from east to westA The concept of the rocket, or rather the mechanism behind the idea of propellingan object into the air, has been around for well over two thousand years. However, it wasnt until the discovery of the reaction principle, which
2、was the key to spacetravel and so represents one of the great milestones in the history of scientificthought, that rocket techn0108y was able to develop. Not only did it solve aproblem that had intrigued man for ages, but, more importantly, it literally openedthe door to exploration of the universe.
3、BAn intellectual breakthrough, brilliant though it may be, does not automaticallyensure that the transition is made from theory to practice. Despite the fact thatrockets had been used sporadically for several hundred years, they remained arelatively minor artefact of civilization until the twentieth
4、 century. Prodigious effortsaccelerated during two world wars, were required before the technology ofprimitive rocketry could be translated into the reality of sophisticated astronauts. Itis strange that the rocket was generally ignored by writers of fiction to transport theirheroes to mysterious re
5、alms beyond the Earth, even though it had been commonlyused in fireworks displays in China since the thirteenth century. The reason is thatnobody associated the reaction principle with the idea of travelling through spaceto a neighboring world. CA simple analogy can help us to understand how a rocke
6、t operates. It is much likea machine gun mounted on the rear of a boat. In reaction to the backward dischargeof bullets, the gun, and hence the boat, move forwards. A rocket motors bulletsare minute, high-speed particles produced by burning propellants in a suitablechamber. The reaction to the eject
7、ion of these small particles causes the rocket tomove forwards. There is evidence that the reaction principle was applied practicallywell before the rocket was invented. In his Noctes Atticae or Greek Nights, AulusGellius describes the pigeon of Archytas, an invention dating back to about 360BC. Cyl
8、indrical in shape, made of wood, and hanging from string, It was moved to and fro by steam blowing out from small exhaust ports at either end. The reactionto the discharging steam provided the bird with motive power. DThe Invention of rockets Is linked inextricably with the invention of black powder
9、.Most historians of techn0108Y credit the ChInese with its discovery. They base theirbellef on studies of Chinese writings or on the notebooks of,early Europeans whosettled in or made long visits to China to study its history rand civilisation. It isprobable that, some tIme in the tenth century, bla
10、ck powder was first compoundedfrom its basic ingredients of saltpetre, charcoal and sulphur. But this does not meanthat it was immediately used to propel rockets. By the thirteenth century, powder-propelled fire arrows had become rather common. The Chinese relied on this typeof technological develop
11、ment to produce incendiary projectiles of many sorts, explosive grenades and possibly cannons to repel their enemies. One such wewas the basket of fire or, as directly translated from Chinese, the arrows like Ileopards. The 0.7 metre-long arrows, each with a long tube of gunpowder at anear the point
12、 of each arrow, could be fired from a long, octagonal-shaped bat the same time and had a range of 400 paces. Another weapon was the arrca flying sabre, which could be fired from crossbows. The rocket, placed in a position to other rocket-propelled arrows, was designed to increase the ran! small iron
13、 weight was attached to the l.5m bamboo shaft, just below the feai to increase the arrows stability by moving the centre of gravity to a position tothe rocket. At a similar time, the Arabs had developed the egg which moveburns. This egg was apparently full of gunpowder and stabilized by a l.5m. Iwas
14、 fired using two rockets attached to either side of this tail.EIt was not until the eighteenth century that Europe became seriously interested inthe possibilities of using the rocket itself as a weapon of war andother weapons. Prior to this, rockets were used only in pyrotechnic disincentive for the
15、 more aggressive use of rockets came not from within the Europeancontinent but from far-away India, whose leaders had built up a corps of rocketeersand used rockets successfully against the British in the late eighteenth century. TheIndian rockets used against the British were described by a British
16、 Captain servingin India as an iron envelope about 200 millimetres long and 40 millimetres indiameter with sharp points at the top and a 3m-long bamboo guiding stick. In theearly nineteenth century the British began to experiment with incendiar: rockets. The British rocket differed from the Indian v
17、ersion in that it was completelyencased in a stout, iron cylinder, terminating in a conical head, measuring one metrein diameter and having a stick almost five metres long and constructedway that it could be firmly attached to the body of the rocket. The Americansdeveloped a rocket, complete with it
18、s own launcher, to use against the Mexicans inthe mid-nineteenth century. A long cylindrical tube was propped up by two sticksand fastened to the top of the launcher, thereby allowing the rockets to be insertedand lit from the other end. However, the results were sometimes not thatimpressive as the
19、behaviour of the rockets in flight was less than predictable.FSince then, there have been huge developments in rocket technology, oftendevastating results in the forum of war. Nevertheless, the modern daysprograms owe their success to the humble beginnings of those in previous centwho developed the
20、foundations of the reaction principle. Who knows what willbe like in the future?C3 TEST1 PASSAGE 2:The risks of cigarette smokeDiscovered in the early 1800s and named nicotianine, the oily essence now called nicotine is the main active ingredient of tobacco. Nicotine, however, is only a small compon
21、ent of cigarette smoke, which contains more than 4,700 chemical compounds, including 43 cancer-causing substances. In recent times, scientific research has been providing evidence that years of cigarette smoking vastly increases the risk of developin3 fatal medical conditions, In addition to being r
22、esponsible for more than 85 per cent of lung cancers, smoking is associated with cancers of, amongst others, the mouth, stomach and kidneys, and is thought to cause about 14 per cent of leukemia and cervical cancers. In 1990, smoking caused more than 84,000 deaths, mainly resulting from such problem
23、s as pneumonia, bronchitis and influenza. Smoking, it is believed, is responsible for 30 per cent of all deaths from cancer and clearly represents the most important preventable cause of cancer in countries like the United States today.Passive smoking, the breathing in of the side-stream smoke from
24、the burning 0f tobacco between puffs or of the smoke exhaled by a smoker, also causes a serious health risk. A report published in 1992 by the US Environmental Protection Agency (EPA) emphasized the health dangers, especially from side-stream smoke. This type of smoke contains more, smaller particle
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