2005年6月18日英语六级试题及答案_第3页

　　Questions 21 to 25 are based on the following passage.

　　Supporters of the biotech industry have accused an American scientist of misconduct after she testified to the New Zealand government that a genetically modified(GM) bacterium could cause serious damage if released.

　　The New Zealand Life Sciences Network, an association of pro-GM scientists and organisations, says the view expressed by Elaine Ingham, a soil biologist at Oregon State University in Corvallis, was exaggerated and irresponsible. It has asked her university to discipline her.

　　But Ingham stands by her comments and says the complaints are an attempt to silence her. "They're trying to cause trouble with my university and get me fired," Ingham told New Scientist.

　　The controversy began on 1 February, when Ingham testified before New Zealand's Royal Commission on Genetic Modification, which will determine how to regulate GM organisms. Ingham claimed that a GM version of a common soil bacterium could spread and destroy plants if released into the wild. Other researchers had previously modified the bacterium to produce alcohol from organic waste. But Ingham says that when she put it in soil with wheat plants, all of the plants died within a week.

　　"We would lose terrestrial(陆生的) plants……this is an organism that is potentially deadly to the continued survival of human beings," she told the commission. She added that the U.S. Environmental Protection Agency(EPA) canceled its approval for field tests using the organism once she had told them about her research in 1999.

　　But last week the New Zealand Life Sciences Network accused Ingham of "presenting inaccurate, careless and exaggerated information" and "generating speculative doomsday scenarios(世界末日的局面) that are not scientifically supportable". They say that her study doesn't even show that the bacteria would survive in the wild, much less kill massive numbers of plants. What's more, the network says that contrary to Ingham's claims, the EPA was never asked to consider the organism for field trials.

　　The EPA has not commented on the dispute. But an e-mail to the network from Janet Anderson, director of the EPA's bio-pesticides(生物杀虫剂) division, says "there is no record of a review and/or clearance to field test" the organism.

　　Ingham says EPA officials had told her that the organism was approved for field tests, but says she has few details. It's also not clear whether the organism, first engineered by a German institute for biotechnology, is still in use.

　　Whether Ingham is right or wrong, her supporters say opponents are trying unfairly to silence her.

　　"I think her concerns should be taken seriously. She shouldn't be harassed in this way," says Ann Clarke, a plant biologist at the University of Guelph in Canada who also testified before the commission. "It's n attempt to silence the opposition."

　　21. The passage centers on the controversy         .

　　A) between American and New Zealand biologists over genetic modification

　　B) as to whether the study of genetic modification should be continued

　　C) over the possible adverse effect of a GM bacterium on plants

　　D) about whether Elaine Ingham should be fired by her university

　　22. Ingham insists that her testimony is based on         .

　　A) evidence provided by the EPA of the United States

　　B) the results of an experiment she conducted herself

　　C) evidence from her collaborative research with German biologists

　　D) the results of extensive field tests in Corvallis, Oregon

　　23. According to Janet Anderson, the EPA        .

　　A) has cancelled its approval for field tests of the GM organism

　　B) hasn't reviewed the findings of Ingham's research

　　C) has approved field tests using the GM organism

　　D) hasn't given permission to field test the GM organism

　　24. According to Ann Clarke, the New Zealand Life Sciences Network         .

　　A) should gather evidence to discredit Ingham's claims

　　B) should require that the research by their biologists be regulated

　　C) shouldn't demand that Ingham be disciplined for voicing her views

　　D) shouldn't appease the opposition in such a quiet way

　　25. Which of the following statements about Ingham is TRUE?

　　A) Her testimony hasn't been supported by the EPA.

　　B) Her credibility as a scientist hasn't been undermined.

　　C) She is firmly supported by her university.

　　D) She has made great contributions to the study of GM bacteria.

　　Questions 26 to 30 are based on the following passage.

　　Every fall, like clockwork, Linda Krentz of Beaverton, Oregon, felt her brain go on strike. "I just couldn't get going in the morning," she says. "I'd get depressed and gain 10 pounds every winter and lose them again in the spring." Then she read about seasonal affective disorder, a form of depression that occurs in fall and winter, and she saw the light-literally. Every morning now she turns on a specially constructed light box for half an hour and sits in front of it to trick her brain into thinking it's still enjoying those long summer days. It seems to work.

　　Krentz is not alone. Scientists estimate that 10 million Americans suffer from seasonal depression and 25 million more develop milder versions. But there's never been definitive proof that treatment with very bright lights makes a difference. After all, it's hard to do a double-blind test when the subjects can see for themselves whether or not the light is on. That's why nobody has ever separated the real effects of light therapy from placebo(安慰剂) effects.

　　Until now. In three separate studies published last month, researchers report not only that light therapy works better than a placebo but that treatment is usually more effective in the early morning than in the evening. In two of the groups, the placebo problem was resolved by telling patients they were comparing light boxes to a new anti-depressant device that emits negatively charged ions(离子). The third used the timing of light therapy as the control.

　　Why does light therapy work? No one really knows. "Our research suggests it has something to do with shifting the body's internal clock," says psychiatrist Dr. Lewey. The body is programmed to start the day with sunrise, he explains, and this gets later as the days get shorter. But why such subtle shifts make some people depressed and not others is a mystery.

　　That hasn't stopped thousands of winter depressives from trying to heal themselves. Light boxes for that purpose are available without a doctor's prescription. That bothers psychologist Michael Terman of Columbia University. He is worried that the boxes may be tried by patients who suffer from mental illness that can't be treated with light. Terman has developed a questionnaire to help determine whether expert care is needed.

　　In any event, you should choose a reputable manufacturer. Whatever product you use should emit only visible light, because ultraviolet light damages the eyes. If you are photosensitive(对光敏感的), you may develop a rash. Otherwise, the main drawback is having to sit in front of the light for 30 to 60 minutes in the morning. That's an inconvenience many winter depressives can live with.

　　26. What is the probable cause of Krentz's problem?

　　A) An unexpected gain in body weight.

　　B) Unexplained impairment of her nervous system.

　　C) Weakening of her eyesight with the setting in of winter.

　　D) Poor adjustment of her body clock to seasonal changes.

　　27. By saying that Linda Krentz "saw the light"(Line 4, Para. 1), the author means that she "         ".

　　A) learned how to lose weight

　　B) realized what her problem was

　　C) came to see the importance of light

　　D) became light-hearted and cheerful

　　28. What is the CURRENT view concerning the treatment of seasonal depression with bright lights?

　　A) Its effect remains to be seen.

　　B) It serves as a kind of placebo.

　　C) It proves to be an effective therapy.

　　D) It hardly produces any effects.

　　29. What is psychologist Michael Terman's major concern?

　　A) Winter depressives will be addicted to using light boxes.

　　B) No mental patients would bother to consult psychiatrists.

　　C) Inferior light boxes will emit harmful ultraviolet lights.

　　D) Light therapy could be misused by certain mental patients.

　　30. Which of the following statements is TRUE?

　　A) Winter depressives prefer light therapy in spite of its inconvenience.

　　B) Light therapy increases the patient's photosensitivity.

　　C) Eye damage is a side effect of light therapy.

　　D) Light boxes can be programmed to correspond to shifts in the body clock.