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38. Amphibianpopulations are declining in numbers worldwide. Not coincidentally, the earth’sozone layer has been continuously depleted throughout the last 50 years.Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that iscontinuously produced by the sun, and which can damage genes. Becauseamphibians lack hair, hide, or feathers to shield them, they are particularlyvulnerable to UV-B radiation. In addition, their gelatinous eggs lack theprotection of leathery or hard shells. Thus, the primary cause of the decliningamphibian population is the depletion of the ozone layer. Each of the following,if true, would strengthen the argument EXCEPT: (A) Of the varioustypes of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes. (B) Amphibianpopulations are declining far more rapidly than are the populations of nonamphibianspecies whose tissues and eggs have more natural protection from UV-B. (C) Atmosphericozone has been significantly depleted above all the areas of the world in whichamphibian populations are declining. (D) The naturalhabitat of amphibians has not become smaller over the past century. (E) Amphibianpopulations have declined continuously for the last 50 years.
答案：D 以下是别人的解答思路：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。
A答案存疑，我觉得原文的conclusion是ozone的破坏是A减少的主要原因，并不强调UVB，A选项取非不能削若结论，所以A选项本身也不能加强结论。A选项取非－ozone阻挡的破坏基因的射线不止UVB一种－不影响结论（zone的破坏是A减少的主要原因）。
求讲解～
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发表于 2019-5-9 18:13:37
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