关于assumption和strengthen？

lanningxin

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 thefollowing, if true, would strengthen the argument EXCEPT:

A.     Of the various types ofradiation blocked by atmospheric ozone, UV-B is the only type that can damagegenes.

B.     Amphibian populations aredeclining far more rapidly than are the populations of non-amphibian specieswhose tissues and eggs have more natural protection from UV-B.

C.     Atmospheric ozone has beensignificantly depleted above all the areas of the world in which amphibianpopulations are declining.

D.     The natural habitat ofamphibians has not become smaller over the past century.

E.     Amphibian populations havedeclined continuously for the last 50 years.

选D。

答案说，D是中性评价，既不strengthen，也不weaken。

但是我认为，D相当于是排除了“amphibian变少”的独立第三方因素，从而对结论“臭氧减少导致amphibian变少”构成了支持。

这么一来，D就不该被except。

不知诸大神怎么看？

alzn2765

这题是LSAT CR Powerscore里的原题，答案是A。
不管你哪里看到的这个题，答案都错的材料就不要看了。

你那么措辞错误（D是“他因”，不是“独立第三因素”。独立第三因是因果推理才有的，果因推理里没有。），要么题型理解错误（你可能错误把这题当成因果推理了）。

这题A选项的错误很明显：无关，除非代入额外假设
你再仔细读一边题：
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.
这里面讲了UV-B radiation可以伤害amphibian的两个原因：1. amphibians皮肤裸露缺乏对radiation的保护；2. 蛋也缺乏保护
这两个原因里哪里讲了是因为UV-B可以damage genes导致了amphibians的decline的？
可以damage genes是UV-B的一个特点，但谁告诉你UV-B导致amphibian减少是因为UV-B的这个特点了？如果我说UV-B可以发电，除非题里说了amphibian是被电死的，否则amphibian怎么死的就跟UV-B能不能发电没关系。我还可以说的更夸张一点儿：UV-B可以导致动物把自己爽死。只要题里没说amphibians是爽死的，就跟UV-B的这个特点没关系。
所以，A如果可以加强，必须需要一个额外的条件，这个条件题里没给：amphibians的decline跟radiation的damage genes有直接关系。没有这个条件，damage genes都跟amphibians没关系，UV-B是不是唯一的damage genes的radiation就更没有半毛钱关系了。

你被题干中的一句废话成功的忽悠了，仔细读题，题里没说的，千万别自己瞎想。

lanningxin

alzn2765 发表于 2016-4-9 03:13
这题是LSAT CR Powerscore里的原题，答案是A。
不管你哪里看到的这个题，答案都错的材料就不要看了。

谢谢，这个是费费逻辑宝典里的，我当时选的也是A。