[外语类试卷]考博英语模拟试卷50及答案与解析.doc

1、考博英语模拟试卷 50及答案与解析 一、 Reading Comprehension 0 For farmers hoping for a healthy harvest, the best place to turn for help these days is the Monsanto Corp. One of the worlds leading biotechnology companies and lately a pioneer in genetically engineered seeds-Monsanto has been incorporating flashy traits

2、 like herbicide and pest resistance into everything from canola to corn. But such super crops dont come cheap. Farmers pay a premium for Monsanto seeds, and to make sure they keep paying, the company requires them to sign an agreement promising not to plant seeds their crops produce. If farmers want

3、 the same bountiful harvest next year, they must return to the company for a new load of seeds. While this arrangement makes sense for Monsanto, it works only if farmers honor it-something thats difficult to police in the U. S. and almost impossible in the developing world. Now, however, Monsanto ho

4、pes to enforce biologically what it cannot enforce contractually. With the help of clever genes currently in development, future Monsanto crops may be designed with a new feature in mind: sterility (不育 ). No sooner will the companys plants mature than the seeds they carry, will lose the ability to r

5、eproduce. From Monsantos point of view, the set of new genes-which others have nicknamed Terminator-is a perfectly legitimate way to protect their intellectual-property rights. Not everybody agrees. Let the new science take hold, opponents ware darkly, and farmers could find themselves coming to Mon

6、santo, seed cup in hand, paying whatever the company demands before they can plant that seasons crop. Worse still, some doomsday stories suggest, pollen (花粉 )from Terminator plants could drift with the wind like a toxic cloud, cross with ordinary crops or wild plants, and spread from species to spec

7、ies until flora all around the world had been suddenly and irreversibly sterilized. No serious scientist thinks anything so disastrous will come to pass. For Monsanto, however, with a technology in its pocket and a fight on its hands, the situation is about as grim as it can get- at least in terms o

8、f public relations. “From a marketing perspective, its pathological (病态的 ). This is a question of who controls the seeds of life.“ 1 Before Terminator, farmers _. （ A） are required to buy new load of seeds every year （ B） axe often caught by the police replanting the seeds （ C） can replant the seeds

9、 under the permission from Monsanto （ D） obey the agreements signed with Monsanto 2 According to Monsanto, the invention of Terminator will NOT _. （ A） stop illegal replanting of seeds in the developing countries （ B） protect their intellectual-property fights （ C） biologically carry out the agreeme

10、nts with the farmers （ D） make all plants sterilized 3 According to the opponents, Terminator will do all the following EXCEPT that _. （ A） Terminator will result in raising the seed price （ B） Terminator will make corns not mature to bear seeds （ C） Terminator will contaminate ordinary crops （ D） T

11、erminator will not be poisonous to other plants 4 Whats the tone of the author towards “Terminator? （ A） Objective. （ B） Mildly critical. （ C） Indifferent. （ D） Pessimistic. 5 The best title for the passage will be _. （ A） The Suicide Seeds （ B） Monsanto-Leading Biotech Company （ C） Sterility in Bio

12、logy （ D） Against New Science 5 The molecules of carbon dioxide in the Earths atmosphere affect the heat balance of the Earth by acting as a one-way screen. Although these molecules allow radiation at visible wavelengths, where most of the energy of sunlight is concentrated, to pass through, they ab

13、sorb some longer wave- length, infrared emissions radiated from the Earths surface, radiation that would otherwise be transmitted back into space. For the Earth to maintain a constant average temperature, such emissions from the planet must balance incoming solar radiation. If there were no carbon d

14、ioxide in the atmosphere, heat would escape from the Earth much more easily. The surface temperature would be so much lower that the oceans might be a solid mass of ice. Today, however, the potential problem is too much carbon dioxide. The burning of fossil fuels and the clearing of forests have inc

15、reased atmospheric carbon dioxide by about 15 percent in the last hundred years, and we continue to add carbon dioxide to the atmosphere. Could the increase in car- bon dioxide cause a global rise in average temperature7 Mathematical models that allow us to calculate the rise in temperature as a fun

16、ction of the increase indicate that the answer is probably yes. Under present conditions a temperature of - 18 can be observed at an altitude of 5 to 6 kilo-meters above the Earth. Below this altitude (called the radiating level), the temperature increases by about 6 per kilometer approaching the Ea

17、rths surface, where the average temperature is about 15 . An increase in the amount of carbon dioxide means that there are more molecules of carbon dioxide to absorb infrared radiation. As the capacity of the atmosphere to absorb infrared radiation increases, the radiating level and temperature of t

18、he surface must rise. One mathematical model predicts that doubling the atmospheric carbon dioxide would raise the global mean surface temperature by 2.5 . This model assumes that the atmospheres relative humidity remains constant and the temperature decreases with altitude at a rate of 6.5 per kilo

19、meter. The assumption of constant relative humidity is important, because water vapor in the atmosphere is another efficient absorber of radiation at infrared wavelengths. Because warm air can hold more moisture than cool air, the relative humidity will be constant only if the amount of water vapor

20、in the atmosphere increases as the temperature rises. Therefore, more infrared radiation would be absorbed and reradiated back to the Earths surface. The resultant warming at the surface could be expected to melt snow and ice, reducing the Earths reflectivity. More solar radiation would then be abso

21、rbed leading to further increase in temperature. 6 According to the passage, the greatest part of the solar energy that reaches the Earth is _. （ A） reflected back to space by snow and ice （ B） concentrated at visible wavelengths （ C） absorbed by carbon dioxide molecules （ D） absorbed by atmospheric

22、 water vapor 7 According to the passage, which of the following is TRUE of the last hundred years? （ A） Fossil fuels were burned for the first time. （ B） The average temperature at the Earths surface has become 2 cooler. （ C） The amount of carbon dioxide in the atmosphere has increased measurably. （

23、 D） The amount of farmland worldwide has doubled. 8 Which of the following best describes the authors attitude toward the increasing amount of carbon dioxide in the atmosphere and its consequences? （ A） Objective yet concerned. （ B） Angry yet resigned. （ C） Completely detached. （ D） Incredulous. 9 I

24、t can be concluded from information contained in the text that the average temperature at an altitude of I kilometer above the Earth is about _. （ A） 15 （ B） -18 （ C） 2.5 （ D） 9 10 The primary purpose of the passage is to _. （ A） discuss the significance of increasing the amount of carbon dioxide in

25、 the atmosphere （ B） warn of the dangers of continued burning of fossil fuels （ C） explain how a constant temperature is maintained in the Earths surface （ D） demonstrate the usefulness of mathematical models in predicting long-range climatic change 10 Our species evolved on the move. Recent researc

26、h on the effects of exercise and the consequences of sedentary living has shown that physical activity is crucial to the proper processing of foods that we eat. In fact, most of the chronic and often life-threatening ailments that besiege Americans in epidemic proportions could be tempered by regula

27、r exercise. Among them are heart disease, diabetes, high blood pressure, arthritis, and osteoporosis. But lets face it: most people are not motivated to exercise by what it may do for them 20 years down the pike. What gets people like me out moving every day is what exercise does for me right now, e

28、specially how it allows me to enjoy eating without gaining. I, along with millions of Americans, have discovered that exercise is the key to permanent and painless weight control. After hearing a description of my usual daily exercise schedule-a morning run or bike ride and an evening swim, sometime

29、s with an hour of tennis in between-some people remark, “Wouldnt it be a lot easier to eat one less bagel a day and skip all that exercise?“ My answer is, “Easier, yes, but not nearly as effective nor as much fun.“ Heres why exercise, not dieting, is best route to a leaner, lighter you. Far better f

30、or your health and, your future to lose primarily fat is in the first place. The only way to do that is through exercise, which uses body fat as its main source of energy. You may not see that initial rapid (but false) weight loss, but what you lose will be what you want to lose-fat, not muscle or w

31、ater. Your loss will be permanent, too. If it s any consolation (安慰 ), studies have shown that in most cases, the faster people lose weight, the more likely they are to regain it. Slow loss, then, is the secret to lasting success. If you want to lose weight faster than you can with just exercise, si

32、mply combine exercise with a reduced-calorie diet. Researchers at the University of California, Davis, showed that exercise could counter the metabolism-lowering effect of a low-calorie diet in many people, it also seems to curb the adverse caloric effect of aging on body metabolism. Whereas ordinar

33、ily your metabolism would slow down as you get older (which is one reason people get fatter in middle age even though they dont eat more), if you continue to exercise regularly, you may keep your youthful, metabolic rate by maintaining a muscular body instead of losing muscle and putting on pounds o

34、f fat. 11 What can be inferred from the passage? （ A） The slower people lose weight, the less likely they are to achieve their goals. （ B） People who are on diet merely lose muscle and water. （ C） Regular exercises may reduce the chance of getting certain chronic diseases. （ D） Physical activity use

35、 muscle tissue as its main source of energy. 12 Which of the following statements about weight control is NOT TRUE? （ A） The exercise is the secret to permanent and successful weight control. （ B） Combining exercises with a reduced-calorie diet makes it easier to lose weight. （ C） Healthy weight con

36、trol means losing primarily fat, not muscle or water. （ D） Eat less and skip the exercise is an easy and effective way of losing weight. 13 Most middle-aged people get fatter, mainly because _. （ A） they made dietary changes when they grow old （ B） of their sedentary living （ C） they dont exercise r

37、egularly （ D） the chemical activity in their body that uses the food to produce energy slows down 14 Which of the following would be the best title for the passage? （ A） Eating Without Gaining. （ B） Exercise-An Effective Weight-loss Tool. （ C） Metabolic Changes in Human Body. （ D） Ways of Weight Con

38、trol. 15 The passage is mainly about _. （ A） how to keep fit （ B） how to lose weight （ C） the benefits brought about by regular exercises （ D） exercises and diet 15 Researchers have recently found a connection between disease and stressful situations. To test this theory, psychologists are trying to

39、 find a link between the brain and the immune system. The immune system in our bodies fights the bacteria and viruses which cause disease. There- fore, whether or not we are likely to get various diseases depends on how well our immune system works. Biologists used to think that the immune system wa

40、s a separate, independent part of our bodies. Recently, however, they have found that our brain can affect our immune system. This discovery indicates that there may be a connection between emotional factors, such as stress or depression, and illness. Although many doctors in the past suspected a co

41、nnection between emotional factor and disease, they had no proof. Scientists have only recently discovered how the brain and the immune sys- tem function. Before this, no one could see a link between them. As a result, medical science never seriously considered the idea that psychological factors co

42、uld cause disease. Several recent studies showed a connection between stress and illness, for example, researchers went to an American military school to study the students. They found that the sick students there had a lot of academic pressure and wanted to achieve, but they were not very good stud

43、ents. In a similar study, researchers studied a group of student nurses and found that the nurses who developed cold sores were the ones who described themselves as generally unhappy people. In addition to these results, which support their theory, researchers are also looking for proof that stress

44、can damage the immune system. Researchers studied recently bereaved people, i. e. , people whose loved ones have just died, because they are more likely to become ill or die. By examining the immune system of recently bereaved people, the researchers made an important discovery. They examined some w

45、hite blood cells which are an important part of the immune system. They were not functioning properly. The fact that they were not working correctly indicates that severe psycho- logical stress, such as a loved ones death, may damage an important part of our immune system. There is still no positive

46、 proof of a connection between the immune system and psychological factors. Researchers also say that the results of the studies on bereaved people could have a different explanation. For example, bereaved people often sleep and eat less than normal, or may drink alcohol or take medication. These fa

47、ctors can also affect the immune system. More research is needed to clearly establish the connection between the immune system and psychological factors. 16 The study on the military school students indicated that _. （ A） life in the school was very stressful （ B） disease could be caused by psycholo

48、gical factors （ C） the good students were likely to fall ill （ D） stress often made students unhappy 17 The immune system _. （ A） used to be unconnected with the brain （ B） causes a lot of stress to people （ C） can be affected by emotional factors （ D） functions independently 18 In the past, many do

49、ctors _. （ A） never thought of any possible link between stress and illness （ B） hardly considered emotional factors when dealing with a patient （ C） discovered that the brain and the immune system functioned independently （ D） found that diseases were caused by psychological factors 19 Which of the following is NOT TRUE according to the passage? （ A） Unhappiness may cause disease. （ B） Drinking alcohol may cause damage to the immune system. （ C） too much sorrow is harmful to the imm