[外语类试卷]考博英语模拟试卷49及答案与解析.doc

1、考博英语模拟试卷 49及答案与解析 一、 Reading Comprehension 0 The great advance in rocket theory 40 years ago showed that liquid-fuel rockets were far superior in every respect to the skyrocket with its weak solid fuel, the only kind of rocket then known. However, during the last decade, large solid-fuel rockets wit

2、h solid fuels about as powerful as liquid fuels have made their appearance, and it is a favorite laymans question to inquire which one is “better“. The question is meaningless; one might as well ask whether a gasoline or a diesel engine is “better“. It all depends on the purpose. A liquid-fuel rocke

3、t is complicated, but has the advantage that it can be controlled beautifully. The burning of the rocket engine can be stopped completely: it can be re-ignited when desired. In addition, the thrust can be made to vary by adjusting the speed of the fuel pumps. A solid-fuel rocket, on the other hand,

4、is rather simple in construction, though hard to build when a really large size is desired. But once you have a solid-fuel rocket, it is ready for action at very short notice. A liquid-fuel rocket has to be fueled first and cannot be held in readiness for very long after it has been fueled. However,

5、 once a solid-fuel rocket has been ignited, it will keep burning. It cannot be stopped and re-ignited whenever desired (it could conceivably be stopped and re-ignited after a pre-calculated time of burning has elapsed) and its thrust cannot be varied. Because a solid-fuel rocket can be kept ready fo

6、r a long time, most military missiles employ solid fuels, but manned space flight needs the fine adjustments that can only be provided by liquid fuels. It may be added that a liquid-fuel rocket is an expensive device; a large solid-fuel rocket is, by comparison, cheap. But the solid fuel, pound per

7、pound; costs about 10 times as much as the liquid fuel. So you have, on the one, hand, an expensive rocket with a cheep fuel and on the other hand a comparatively cheap rocket with an expensive fuel. 1 The author feels that a comparison of liquid and solid-fuel rockets shows that _. （ A） neither typ

8、e is very economical （ B） the liquid-fuel rocket is best （ C） each type has certain advantages （ D） the solid-fuel rocket is hest 2 The most important consideration for manned space flight is that the rocket be _. （ A） inexpensive to construct （ B） capable of lifting heavy spacecraft into orbit （ C）

9、 easily controlled （ D） inexpensive to operate 3 Solid fuel rockets are expensive to operate because of their _. （ A） size （ B） fuel （ C） construction （ D） complicated engines 4 Which of the following statements is not characteristic of liquid-fuel rockets? （ A） The fuel is cheap. （ B） They are chea

10、p to build. （ C） They can be stopped and re-ignited. （ D） They must be used soon after fueling. 5 The author tells us that （ A） whether a liquid-fuel or a solid-fuel rocket is better depends on the purpose （ B） neither type is superior （ C） forty years ago, large solid-fuel rockets with solid fuels

11、as powerful as liquid fuels were made （ D） the thrust can be made to vary by adjusting the direction of the pump 5 Imagine an accident in which a nuclear power plant releases radioactive gas. The cloud starts moving with the wind. Clearly, the authorities will want to evacuate anyone in its path, bu

12、t what is that path? Local wind information is meaningless without information about terrain, a mountain range or series of valleys can divert both wind and gas in unpredictable directions. To make “downwind“ a useful term, scientists at Lawrence Livermore National Laboratory have put the United Sta

13、tes on a computer, the entire United States-every hill, every valley, every mile of seashore. Within minutes of a disaster, they can give meteorologists a context for weather data, and thus the ability to predict how toxic gases might spread. The database for this computer map is a series of altitud

14、e measurements, made over many years by the Defense Department and the U.S. Geological Survey. They represent the height above sea level of over a billion separate points-a grid of points 200 feet apart, spanning the country. Armed with these data, plus a program that manipulates them, a Cray-1 comp

15、uter can produce an image of any piece of terrain, seen from any angle, illuminated by an imaginary sun at any time of day placing the “observer“ at any altitude from zero to 40,000 feet. “We use a technique called ray tracing,“ says Patrick Weidhaas, one of the Livermore computer scientists who wro

16、te the program. The computer is told where the observer is. The program traces an imaginary ray from there outward until it “intersects“ with one of the points of altitude recorded in the machine s memory. The computer then puts a dot of color at the proper place on the screen, and the program trace

17、s another ray. At its highest resolution of 2,000 horizontal and 1,700 vertical dots per picture, the computer has to trace several million rays. Even on the Cray, the most powerful computer in the world, this takes about a minute. Reducing the resolution to 400 300 (a TV screen has 800 x 700) speed

18、s it up to about eight seconds. “We cant produce a movie simulating flight on the screen in real time,“ says Weidhaas. There is a way around the problem: Two movies have been made using still pictures generated by the computer as individual frames. “The results were impressive,“ he says, “but it was

19、 cumbersome to do. At twenty-four frames per second, it takes fourteen hundred separate computer images to make a one-minute film.“ Another limitation. The computer can access only enough memory to cover a 15-mile-square area. An “observer“ high up will see blank spaces beyond those limits. Weidhaas

20、 wants to add information about what overlies the terrain-cities, vegetation, roads, and so on. “Making the image as realistic as possible will make our advice more effective,“ he says, “and might lead to uses we havent thought of yet.“ 6 As used in the first paragraph, terrain most clearly means _.

21、 （ A） available information about the weather （ B） surrounding land area （ C） blank spaces between the mountain ranges （ D） amount of forest per square mile 7 Livermores computer map, in combination with weather reports, might be useful in predicting _. （ A） the path of toxic gases from a nuclear po

22、wer plant explosion （ B） where incoming nuclear missiles might strike （ C） the average annual rainfall for North Dakota （ D） the amount of pollution in the air 8 The information used by the computer to make its detailed maps _. . was gathered by the Defense Department and the U. S. Geological Survey

23、 . shows points roughly 200 feet apart . involves altitude measurements （ A） （ B） and （ C） and （ D） , and 9 Which of the following is the best description of ray tracing? （ A） The computer simulates rays of the sun, filling in areas of light and shadow. （ B） Lines radiate outward from the imagined o

24、bserver and a dot of color is placed where the line intersects with one of the points of altitude in the machines memory. （ C） X-rays are used to trace the outline of the terrain through buildings and trees. （ D） The exact movement of rays is used by private detectives to solve mysteries and locate

25、missing persons. 10 Information about cities, vegetation, and road overlying the terrain _. （ A） has to be eliminated before correct readings can be obtained （ B） would be impossible to convert to data that a computer would accept （ C） might lead to new applications and improve effectiveness of pres

26、ent uses （ D） would make ray tracing obsolete 10 Should doctors ever lie to benefit their patients-to speed recovery or to conceal the approach of death? In medicine as in law, government, and other lines of work, the requirements of honesty of- ten seem dwarfed by greater needs: the need to shelter

27、 from brutal news or to uphold a promise of secrecy. What should doctors say, for example, to a 46-year-old man coming in for a routine physical checkup who, though he feels in perfect health, is found to have a form of cancer? If he asks, should the doctor deny that he is ill, or minimize the gravi

28、ty of the illness? Doctors confront such choices often and urgently. At times, they see important reasons to lie for the patients own sake. In their eyes, such lies differ sharply from self-serving ones. Studies show that most doctors sincerely believe that the seriously ill do not want to know the

29、truth about their condition, and that informing them risks destroying their hope, so that they may re- cover more slowly, or deteriorate faster, perhaps even commit suicide. As one physician wrote: “Ours is a profession which traditionally has been guided by a precept that transcends the virtue of u

30、ttering the truth for truths sake and that is, as far as possibledo no harm.“ Armed with such a precept, a number of doctors may slip into deceptive practices that they assume will “do no harm“ and may well help their patients. But the illusory nature of the benefits such deception is meant to produ

31、ce is now coming to be documented. Studies show that, contrary to the belief of many physicians, an overwhelming majority of patients do want to be told the truth, even about grave illness, and feel betrayed when they learn that they have been misled. We are also learning that truthful information,

32、humanely conveyed, helps patients cope with illness. Not only do lies not provide the “help“ hoped for by advocates of benevolent deception, they invade the autonomy of patients and render them unable to make informed choices concerning their own health. Lies also do harms to those who tell them: ha

33、rm to their integrity and, in the long run, to their credibility. Lies hurt their colleagues as well. The suspicion of deceit undercuts the work of the many doctors who are scrupulously honest with their patients; it contributes to the spiral of lawsuits and of “defensive medicine“, and thus it inju

34、res, in turn, the entire medical profession. 11 Who are most likely to lie for serving purposes? （ A） physicians （ B） surgeons （ C） psychiatrists （ D） lawyers 12 Doctors think that lying to their patients is _. （ A） a medical tradition （ B） to harm their own integrity （ C） to defend medicine （ D） ut

35、tering the truth for truths sake 13 Most patients think that being told the truth of their illness may _. （ A） slow down recovery （ B） lead to suicide in some cases （ C） be too hard for them to accept （ D） help deal with illness 14 Which of the following statements is NOT true according to the autho

36、r? （ A） Doctors are often in a dilemma as to tell the patient his real condition of health. （ B） Doctors reluctance to tell patient truth has no real support in reality. （ C） Doctors lies are different from that of lawyers and government officials. （ D） Doctors and patients hold different views abou

37、t telling truth. 15 What is the authors attitude towards doctors? （ A） sarcastic （ B） praising （ C） objective （ D） appreciative 15 China today is home to 13 billion people-nearly one quarter of the worlds population. The growth of Chinas population is largely the result of modernization, which has b

38、rought with it more food, better medical care, less disease, and fewer epidemics and famines. The death rate in China has decreased, and more children survive. The higher survival rate in China means that more people are entering childbearing age. This population growth was threatening to destroy Ch

39、inas chances to become a richer country: just providing food and basic necessities for everyone would consume all of its economic gains. To tame the explosive population growth, the Chinese government launched a drastic policy of allowing one child per family. To enforce this policy, the government

40、has a variety of incentives for those who comply and punishment for those who do not. For example, couples who have only one child get a monthly pay until the child is fourteen, special consideration for scarce housing, free medical care, and extra pension benefits. The pressure to conform is powerf

41、ul. Couples who ignore the states directive suffer social disgrace and economic penalties. The family-planning policy, instituted in China in 1979, has been remarkably effective (though considerably more so in cities than in the countryside). Births to women of childbearing age have fallen dramatica

42、lly-to about 2.5 children for every woman. China may eventually succeed in balancing its population growth, but in doing so, it is creating a new problem. The irony is that because of the very success of Chinas population policy, the Chinese population is aging rapidly. In 1982, 5% of the population

43、 was over age 64. In 2010, about 9% will be over 64, and in 2050, 25% will be. At the family level, children without brothers or sisters will each have to care for two aging parents. At the national level, the great numbers of aging people will tax the societys resources. China shares this problem-a

44、 rapidly aging population with- out a large enough following generation to support it-with many of the developed nations of the world. 16 The primary purpose of this passage is to _. （ A） predict the population problem in China （ B） explain why the family-planning policy is adopted in China （ C） ill

45、ustrate the result of family-planning policy （ D） demonstrate the cause and effect of the family-planning policy 17 According to the passage, all of the following are the causes for the population explosion in China except _. （ A） better life （ B） decreased death rate （ C） better education （ D） bett

46、er health 18 According to the passage, China is in a population dilemma in the sense that _. （ A） it is difficult to carry out the family-planning policy （ B） Chinese population will continue to increase rapidly in the near future （ C） birth-rate decreases but the percentage of old people increases

47、（ D） more old people survive in the society 19 To punish those who violate the family-planning policy the Chinese government does which of the following7 （ A） Put them into prison. （ B） Fine those couples. （ C） Reduce their wages. （ D） Advise them to observe the rule. 20 All of the following can be

48、inferred form the passage except that _. （ A） many developed nations suffer from the problem of a rapidly aging population （ B） the family-planning policy meets more difficulty in the countryside than in cities （ C） the increasing number of aged people is a result of the reduced birth-rate （ D） in t

49、he year of 2010 each child will have to look after one parent 20 Americans had always been preoccupied with reforming their society, with “making it over,“ and between the 1890s and the end of the First World War, the reform spirit intensified. More and more people tried to address the problem of their time directly, to impose order on a confusing world, and, especially, to create a conflict-free society. Their efforts, inspired by a complicated mixture of calcula