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38. Amphibian populations are declining in numbers worldwide. Not coincidentally, the earth’s ozone layer has been continuously depleted throughout the last 50 years. Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that is continuously produced by the sun, and which can damage genes. Because amphibians lack hair, hide, or feathers to shield them, they are particularly vulnerable to UV-B radiation. In addition, their gelatinous eggs lack the protection of leathery or hard shells. Thus, the primary cause of the declining amphibian population is the depletion of the ozone layer.
Each of the following, if true, would strengthen the argument EXCEPT:
A. Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. B. Amphibian populations are declining far more rapidly than are the populations of non-amphibian species whose tissues and eggs have more natural protection from UV-B. C. Atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining. D. The natural habitat of amphibians has not become smaller over the past century. E. Amphibian populations have declined continuously for the last 50 years.
答案：D 思路：原文论述臭氧层的破坏造成UV-B辐射过量是导致两栖动物数量减少的主要原因。 A：支持说明为什么是UV-B而不是其他原因。 B：支持说明为什么UV-B会降低两栖动物的数量。 C：提供空间论据说明臭氧层受损和两栖动物数量减少的相关性。 D：中性评价。不Weaken也不Strengthen. E：提供时间论据说明臭氧层受损和两栖动物数量减少的相关性。 _________________________________________________________________________________________ 以上是讲解里的答案，但是最后的答案汇总里又写的是A 个人也觉得应该是A,因为原题的结论是OZONE被破坏是导致两系动物数量减少的原因，并不是说UV-B是原因，A选项根本就不能支持原文的观点阿。 希望大家讨论下这个题 | 
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发表于 2008-11-6 18:50:00
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