20. GWD26-Q20 In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores; by 1997 they had spent nearly six hours a week. A. chores; by 1997 they had spent nearly six hours a week B. chores; by 1997 that figure had grown to nearly six hours a week C. chores, whereas nearly six hours a week were spent in 1997 D. chores, compared with a figure of nearly six hours a week in 1997 E. chores, that figure growing to nearly six hours a week in 1997 答案是b我选的事a 能解释一下各选项为什么错吗 而且尤其是a 21. GWD-23-Q37 Until recently, trade flows were of interest mainly to economic experts and executives of large corporations, but since the past few years, the movement of goods and services across national boundaries have become the subject of intense public attention all over the world. A. since the past few years, the movement of goods and services across national boundaries have become B. the movement of goods and services across national boundaries since the past few years became C. the movement across national boundaries of goods and services over the past few years have become D. over the past few years, the movement across national boundaries of goods and services are becoming E. over the past few years, the movement of goods and services across national boundaries has become 网上争议大 正确答案给的是a 我选得b 网上好多人说是e 答案到底是哪个 其他的为什么对 答案为什么错阿 22. GWD26-Q22 People who have spent a lot of time in contact with animals often develop animal-induced allergies, some of them quite serious. In a survey of current employees in major zoos, about 30 percent had animal-induced allergies. Based on this sample, experts conclude that among members of the general population who have spent a similarly large amount of time in close contact with animals, the percentage with animal-induced allergies is not 30 percent but substantially more. Which of the following, if true, provides the strongest grounds for the experts’ conclusion? A. A zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation. B. A zoo employee is more likely than a person in the general population to keep one or more animal pets at home C. The percentage of the general population whose level of exposure to animals matches that of a zoo employee is quite small. D. Exposure to domestic pets is, on the whole, less likely to cause animal-induced allergy than exposure to many of the animals kept in zoos. E. Zoo employees seldom wear protective gear when they handle animals in their care. 网上争议大 正确答案到底是哪个啊 能解释一下为什么吗 还有其他的为什么不对阿 37. GWD26-Q37 Sound can travel through water for enormous distances, prevented from dissipating its acoustic energy as a result of boundaries in the ocean created by water layers of different temperatures and densities. A. prevented from dissipating its acoustic energy as a result of B. prevented from having its acoustic energy dissipated by C. its acoustic energy prevented from dissipating by D. its acoustic energy prevented from being dissipated as a result of E. preventing its acoustic energy from dissipating by 答案是c我选的是e 我的为什么错答案为什么对阿 其他的选项为什么不可以 | 
