麻烦各位了，这个题目我老错，求指点，看了前人指点还是不明白

alicejingli

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
，我的问题就是C为啥部队，我知道不是C就是E，但是为啥不选择C呢？难道说是因为E举的是反例所以更优先吗？那我能给按照一个规律记住吗？

jessiecg

C只是重复原文吧，并没有加强假设啊。。

cdwayne

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.


只要注意这个因果关系就可以了


C. Recently discovered samples of the vaccine dating from 1960 still show traces of the virus. (重复原文叙述, 没有支持)
E. In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40. (对照组, 不同实验得不同结果, 支持原文假设"被污染的疫苗是原因")


ps. 楼主的举反例只是支持的其中一个手法, 并不是每一个支持题都会出现, 无须硬记

aven2643

这个题的关键是抓住source这个词
C与E的区别可以通过取非来判断 无需再和M disease建立什么关系了
C取非 只说明recently发现的vaccine里面没有SV40----不能说明vaccine不是SV40 的source----没有削弱source的说法
E取非  说明vaccine 不是source 所以这一项肯定得是成立的

落寞的旅人

有木有人选了B的。。。。求教。
我的理解是：因为现在技术的创新使感染SV40的可能性没有了，所以感染SV40的情况只可能是1960的那一次。。。。求大神指教