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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:

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.

 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.

答案是A，我觉得应该是D吧？

答案就是D，是不是看错了：）

引用FF原文：

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。

技巧：做EXCEPT题如果答案中出现原文没有的专有名词(地名和人名等)一般就选它。

好象都有点道理...麻烦了...

大家再讨论讨论~~~

A 是排除他因，加强原文因果关系。

D 我觉得栖息地变小，并不能说明数量变少吧：） 并没有直接的关系。

Before trying to answer the question, locate the conclusion first. The conclusion is that "ozone layer depletion" is the primary cause of A population's decrease. More UV-B penetration plays a role here. But it's not saying more UV-B penetration is the primary cause of population decrease.

So A is obviously not a "strengthen". If more kinds of radiation could be harmful, ozone layer plays a more important role. If only one kind, as A said, we can say ozone layer protection is relatively not that important. So A could be regarded as a "weaken" or can just be marked as "irrelevant". So, choose A.

For D, it exclude a possibility that something other than "ozone layer depletion" causes A population to decrease. So it strengthens the argument.

同意楼上和5楼的观点

D是排除他因,所以是支持的

恩，细想了一下，承认错误！：）我没有分清文章的主要结论。

应该是两栖类动物数量减少的基本原因是臭氧层的破坏，而不是两栖类动物数量减少的基本原因是UV-B辐射过量。

谢谢大家。