这是个老题了，看了N久的讨论，也没太明白最终是E还是C，还请各位梦友，各位牛

牛们再次能确认一下。除了希望考试别碰到这样的题，难道不能弄个水落石出吗？争

论焦点主要在C 和E上。

简述一下前人的理论依据：C是有因有果的加强，E是无因无果的加强。

谢谢了。不懂的日子真郁闷！

GWD-10-Q9:
Although exposure to asbestos is the primary cause of mesothelioma, a

slow-developing
cancer, researchers believe that infection by the SV40 virus is a

contributing cause, since
in the United States 60 percent of tissue samples from mesotheliomas, but

none from
healthy tissue, contain SV40. SV40 is a monkey virus; however, in 1960

some polio
vaccine was contaminated with the virus. Researchers hypothesize that this

vaccine was
the source of the virus found in mesotheliomas decades later.

Which of the following, if true, most strongly supports the researchers’

hypothesis?

A.     SV40 is widely used as a research tool in cancer laboratories.

B. Changes in the technique of manufacturing the vaccine now prevent
contamination with SV40.

C. Recently discovered samples of the vaccine dating from 1960 still show

traces of the virus.

D. In a small percentage of cases of mesothelioma, there is no history of

exposure to asbestos.

E. In Finland, where the polio vaccine was never contaminated, samples

from mesotheliomas do not contain SV40

firmly support E.

C 只是证明了vaccine被污染的事实，并不能support病菌是通过它传播。
E 从另一个角度证明了vaccine是传播的根源。

In my opinion, it is helpful to read the discussion on this question,

but it's really not that important to know the "standard answer." After

all, the chance that this particular question will appear in the exam is

minimum to none, and even if it does appear, it may not be counted towards

score. (In PP3, 30 out of 41 questions are counted towards score.)

E！答案是正确的

问题是：什么可以加强 研究人员推论出的“这些vaccine是导致M中发现SV40的原因”。

因为C 只是再次说明 SV40存在于Vaccine中，而原文已经正面的肯定 1960年的Vaccine感染了SV40。再次肯定一个已知事实没有作用，不会加强什么。反过来说 即使加强了“这些Vaccine有SV40”，但是这些得了M的人都没有打过这批vaccine，那M中的sv40从哪里来的呢？

E说明 这些有SV40的vaccine是导致 M中发现SV40的源头。因为，没有感染过SV40的vaccine地区的m病种就没有sv40，证明M中发现SV40的必然不是M本身会自然生成的，而是意外传入的，那这种意外的很大可能就是当年感染那批vaccine。所以跟后文的this vaccine直接对应！

无疑E是答案

要支持的结论是this vaccine was the source of the virus found in

mesotheliomas decades later.而不是vaccine was contaminated with the virus

。正像楼上几位说的一样。C只能支持vaccine was contaminated with the virus。

所以C没有提供更多的证据使vaccine was contaminated with the virus（前提）对

结论的证明力变大

E是典型的无因无果型加强