大学英语六级184及答案解析.doc

1、大学英语六级 184及答案解析(总分：427.98，做题时间：132 分钟)一、Part I Writing (3(总题数：1，分数：30.00)1.For this part, you are allowed 30 minutes to write a composition on the topic Fast Food and Traditional Chinese Cuisine. You should write at least 150 words according to the outline given below in Chinese. 1西餐越来越受到中国人的青睐，对你而言

2、中餐和西餐，更喜欢哪种； 2请给出两条以上的理由支持你的观点； 3对全文作一总结。 （分数：30.00）_二、Part II Reading C(总题数：1，分数：71.00)The Debate over Genetically Modified Foods -Rice with built-in Vitamin A that can help prevent blindness in 100 million children suffering from Vitamin A deficiency -A tomato (hat softens more slowly, allowing i

3、t to develop longer on the vine and keep longer on the shelf -Potatoes that absorb less fat when fried, changing the ever-popular French fries from junk food into a more nutritional food -Strawberry crops that can survive frost These are some of the benefits promised by biotechnology. The debate ove

4、r its benefits and safety, however, continues. Do we really need to fear mutant (突变体) weeds, killer tomatoes, and giant corn and will the benefits be delivered? Conventional Breeding Versus Genetically Modified (GM) Crops For thousands of years farmers have used a process of selection and cross bree

5、ding to continually improve the quality of crops. Even in nature, plants and animals selectively breed, thus ensuring the optimum gene pool for future generations. Traditional breeding methods are slow, requiring intensive labor: While trying to get a desirable trait in a bred species, undesirable t

6、raits will appear and breeders must continue the process over and over again until all the undesirables are bred out. In contrast, organisms acquire one specific gene or a few genes together through genetic modification, without other traits included and within a single generation. However, this tec

7、hnology too is inherently unpredictable and some scientists believe it can produce potentially dangerous results unless better testing methods are developed. Traditional breeding is based on sexual reproduction between, like organisms. The transferred genes are similar to genes in the cell they join

8、 They are conveyed in complete groups and in a fixed sequence that harmonizes with the sequence of genes in the partner cell. In contrast, bioengineers isolate a gene from one type of organism and splice (接合) it haphazardly into the DNA of a dissimilar species, disrupting its natural sequence. Furt

9、her, because the transplanted gene is foreign to its new surroundings, it cannot adequately function without a big artificial boost. One of the main differences between conventional and genetically modified crops is that the former involves crosses either within species or between very closely relat

10、ed species. GM crops can have genes either from closely related species or from distant species, even bacteria and viruses. Benefits: One Side of the Debate -Economical benefits GM supporters tell farmers that they stand to reap enormous profits from growing GM crops. Initially, the cost is expensiv

11、e but money is saved on pesticides. To produce the GM crops, modern biotechnology is used which requires highly skilled people and sophisticated and expensive equipment. Large companies need considerable investments in laboratories, equipment and human resources, hence the reason why GM crops are mo

12、re expensive for farmers than traditional crops. GM crops, farmers are told, are a far better option. It takes a shorter time to produce the desired product. It is precise and there are no unwanted genes. -Herbicide-Resistant Crops So what other advantages do GM crops hold for farmers? GM crops can

13、be produced to be herbicide-resistant. This means that farmers could spray these crops with herbicide and kill the weeds, without affecting the crops. In effect, the amount of herbicide used in one season would be reduced, with a subsequent reduction in costs for farmers and consumers. For Ingard co

14、tton, pest-resistance was built into the cotton, hence reducing and even removing the use of pesticides, which are not only expensive but, more importantly, harmful to the environment. Biotechnology companies are even experimenting with crops that can be genetically modified to be drought- and salt-

15、tolerant, or less reliant on fertilizer, opening up new areas to be farmed and leading to increased productivity. However, the claims of less herbicide usage with GM crops have till now not been independently supported by facts. -Better Quality Foods Even animals can be genetically modified to be le

16、aner, grow faster, and consume less food. They could be modified to have special characteristics, such as greater milk production in cows. These modifications again lead to improved productivity for farmers and ultimately lower costs for the consumer. Modified crops could perhaps prevent outbreaks s

17、uch as foot and mouth disease, which has devastated many farmers and local economies. No such products have been released to date; however, some are under consideration for release. For example, GM salmon, capable of growing almost 30 times faster than natural salmon, may soon be approved by the FDA

18、 (Food and Drug Administration) in the U.S. for release into open waters without a single study on the impact on human health or the environment. Risks: the Other Side of the Debate The major concerns of those who oppose GM foods center on the following: -Environmental Damage The problem with GM cro

19、ps is that there is little known about what effect they will have in, say, 20 years time. The genetic structure of any living organism is complex and GM crop tests focus on short-term effects. Not all the effects of introducing a foreign gene into the intricate genetic structure of an organism are t

20、ested. Will the pests that a crop was created to resist eventually become resistant to this crop? Then there is always the possibility that we may not be able to destroy GM crops once they spread into the environment. -Risk to Food Web A further complication is that the pesticide produced in the cro

21、p may unintentionally harm creatures. GM crops may also pose a health risk to native animals that eat them. The animals may be poisoned by the built-in pesticides. Tests in the U.S. showed that 44% of caterpillars of the monarch butterfly died when fed large amounts of pollen (花粉) from GM corn. -Cro

22、ss-Pollination(授粉) Cross-pollination is a concern for both GM crops and conventional breeding, especially with the more serious weeds that are closely related to the crops. With careful management this may be avoided. Genetic modification to herbicide-resistant crops could insert the gene that preve

23、nts the problem. The number of herbicide-tolerant weeds has increased over the years from a single report in 1978 to the 188 herbicide-tolerant weed types in 42 countries reported in 1997. They are an ever-increasing problem and genetic engineering promises to stop it. But will genes from GM plants

24、spread to other plants, creating superweeds and superbugs we wont be able to control? -GM Mix-Ups Humans can inadvertently eat foods that contain GM products meant as animal feed, i.e., crops modified for increased productivity in animals. This happened in the U.S., where traces of a StarLink GM cro

25、p, restricted to use only in feed, were found in taco shells. Apparently no one became ill, but other such occurrences may lead to health problems. -Disease Another concern is disease. Since some crops are modified using the DNA from viruses and bacteria, will we see new diseases emerge? What about

26、the GM crops that have antibiotic-resistant marker genes? Marker genes are used by scientists to determine whether their genetic modification of a plant was successful. Will these antibiotic-resistant genes be transferred to microorganisms that cause disease? We already have a problem with ineffecti

27、ve antibiotics. How can we develop new drugs to fight these new bugs? Conclusion Proponents of GM crops claim that advantages may be many, such as: -improved storage and nutritional quality -pest- and disease-resistance -selective herbicide-tolerance -tolerance of water, temperature and saline extre

28、mes -improved animal welfare -higher yields and quality However, until further studies can show that GM foods and crops do not pose serious threats to human health or the worlds ecosystems, the debate over their release will continue. Living organisms are complex and tampering with their genes may h

29、ave unintended effects. It is in our common interest to support scientists and organizations concerned, such as Friends of the Earth who demand “mandatory labeling of these food products, independent testing for safety and environmental impacts, and liability for harm to be assumed by biotech compan

30、ies“. （分数：71.00）(1).Conventional breeding is a slow, predictable process.（分数：7.10）A.YB.NC.NG(2).Even genes from animals can be used to engineer crops.（分数：7.10）A.YB.NC.NG(3).Safety studies have been done on GM salmon.（分数：7.10）A.YB.NC.NG(4).This article tells us that further studies are needed to asse

31、ss the potential risks of GM foods even though the technology promises many benefits.（分数：7.10）A.YB.NC.NG(5). 1is inherently dangerous unless better testing methods are developed.（分数：7.10）填空项 1:_(6).Growing GM crops is initially 1 but cheaper in the long run.（分数：7.10）填空项 1:_(7).GM fields use 1 herbic

32、ides.（分数：7.10）填空项 1:_(8).No one knows exactly how GM crops will affect the environment because genetic structure is complex and the related tests now mainly study 1.（分数：7.10）填空项 1:_(9).The native animals that eat GM crops might be poisoned by 1.（分数：7.10）填空项 1:_(10).Scientists use 1 to test whether t

33、heir genetic modification of a plant is successful.（分数：7.10）填空项 1:_三、Listening Comprehens(总题数：1，分数：15.00)A.The foggy weather has affected Marys mood.B.They are puzzled about Marys low spirits.C.Mary is dissatisfied with her promotion.D.Mary cares too much about her looks.A.Go to an art exhibition.B.

34、Dine out with an old friend.C.Attend the opening night of a play.D.See his paintings on display.A.Her mother was quite outstanding in academic work.B.She was not particularly interested in going to school.C.Her parents laid great emphasis on academic excellence.D.She helped upgrade the educational l

35、evel of immigrants.A.The machines there were ill maintained.B.Tickets for its members were cheaper.C.It was filled with people all the time.D.It had a reputation for good service.A.Both Sarah and Tom have been awarded doctoral degrees.B.Tom has arranged to meet his bride Sarah in Hawaii.C.Tom was mo

36、re excited than Sarah at the wedding.D.A double blessing has descended upon Tom.A.There were too many questions in the examination.B.The examination was well beyond the course content.C.The examination questions were somewhat too difficult.D.The course prepared him adequately for the examination.A.I

37、ts less time-consuming.B.His wife is tired of cooking.C.Its part of his job.D.He is sick of home-cooked meals.A.He has just started to teach piano lessons.B.He seldom takes things seriously.C.He is very proud of his piano skills.D.He usually understates his achievements.A.Its tedious.B.Its absurd.C.

38、Its justifiable.D.Its understandable.A.Arrange accommodation for her.B.Explain the cause of the cancellation.C.Compensate her for the inconvenience.D.Allow her to take another flight that night.四、Section A(总题数：2，分数：10.00)A.It has broken down before.B.She generally doesnt allow people to borrow it.C.

39、She is trying to sell it.D.She bought it from a friend.A.It shouldnt cost a lot to repair.B.Its probably difficult to drive.C.The woman could probably fix it herself.D.Its rather small.A.He will probably overcharge her.B.He is one of her neighbors.C.He only works on new cars.D.He has fixed her car b

40、efore.A.Help the woman pay the mechanics bill.B.Help the woman fix her car.C.Take the woman to her home.D.Test-drive the womans car.A.A book called Psychology and the Modern Age.B.A social book called the Modern Age.C.A book called Physiology and the Modern Age.D.A book called Sociology and the Mode

41、rn Age.A.The book has been sold.B.The book has been lost.C.The book has been reserved.D.The book has been borrowed by the professor.A.Its down the hall and to the right.B.Its up the hall and to the right.C.Its down the hall and to the left.D.Its up the hall and to the left.A.That way, the book stays

42、 in the library, and all students have a chance to read it.B.That way, the book stays in the library, and not all students have a chance to read it.C.That way, the book stays in the professors, and all students have a chance to read it.D.That way, the book stays in the professors, and not all studen

43、ts have a chance to read it.五、Section B(总题数：3，分数：10.00)A.The government officials.B.The factory owners.C.The criminals.D.The poor and immigrants.A.People needed places to work and live.B.City government was encouraging expansion.C.There were few clearly defined neighborhoods.D.Real estate developmen

44、t was uncontrolled.A.Rapid population growth.B.Corrupt city government.C.Real estate speculators.D.Lack of immigration quotas.A.The whole city becomes noisy.B.Its hard to find a cheap or vacant hotel room.C.It is too hot then.D.The crime rate increases.A.Fly to Amsterdam directly.B.Take the ship.C.F

45、ly to London and take a coach.D.Buy ticket directly from the airlines.A.The bicycle is easily stolen.B.The roads are narrow and unsuitable for bicycles.C.There are many ups and downs in the city so riding a bike is tiring.D.There are too many cars so its unsafe to ride a bike.A.They will be much big

46、ger.B.They will have more seats.C.They will have three wheels.D.They will need intelligent drivers.A.It doesnt need to be refueled.B.It will use solar energy as fuel.C.It will be driven by electrical power.D.It will be more suitable for long distance travel.A.Passengers in the car may be seated faci

47、ng one another.B.The front seats will face forward and the back seats backward.C.Special seats will be designed .for children.D.More seats will be added.A.Choose the right route.B.Refuel the car regularly.C.Start the engine.D.Tell the computer where to go.六、Section C(总题数：1，分数：10.00)The Pentagon is s

48、eeking congressional approval for development of a new weapon able to strike distant targets an hour after they are detected, a newspaper reported on Monday. The International Herald Tribune said the weapon would be a (36) 1version of the submarine-launched Trident-2 missile and be part of a preside

49、nts (37) 2when considering a preemptive (先发制人的) attack. The report quoted U.S. military officials as saying it could be used to hit (38) 3camps, enemy missile sites, suspected caches of weapons of mass (39) 4and other urgent threats. General James Cartwright, the head of the U.S. Strategic Command, said the system would allow U.S. for