Prep2-24

zhuceg

24. (28903-!-item-!-188;#058&004064)
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.

E为正确答案， 请大家帮忙分析一下思路！

ymz

传说中的都烂选少烂。都好选更好

zhuceg

传说中的都烂选少烂。都好选更好 ？？

zanyingsan

以下是引用zhuceg在2009/5/1 19:24:00的发言：
24. (28903-!-item-!-188;#058&004064)
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.

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

now的事跟以前也无关
(C) Recently discovered samples of the vaccine dating from 1960 still show traces of the virus.

这句好像削弱。不知道我理解的对不对。
(D) In a small percentage of cases of mesothelioma, there is no history of exposure to asbestos.

无关
(E) In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40.其实这个选项也是部分支持，因为设定了范围在 Finland 但是相比之下，这个是最好的了。

E为正确答案， 请大家帮忙分析一下思路！

sunjin1988

E是属于无因无果的加强 C不是削弱 我认为C的结论有两种可能性(C) Recently discovered samples of the vaccine dating from 1960 still show traces of the virus 可能是病毒本身就是vaccine产生的而不是vaccine was contaminated with the virus.  如果是这种情况呢？他都会发现病毒啊 所以无法支持结论

rainbowmanutd

E选项就是把原文重复了一遍呀。。 since in the United States 60 percent of tissue samples from mesotheliomas, but none from healthy tissue, contain SV40.原文说了好的tissue不含sv40.E又重复了一遍，重复原文的不是不能选吗

rainbowmanutd

而且结论是 Researchers hypothesize that this vaccine was the source of the virus found in mesotheliomas decades later.
vaccine是发现在m里的virus的源泉
E说Vaccine没有污染，M就不含virus 。这不能说明Vaccine有污染，M就含有virus呀

leosnoon

对，E无因无果。
不过对于C，时间也有问题吧，不能选，原文说found in mesotheliomas （1960后的）decades later， 而C说dating from 1960。排除C

E是属于无因无果的加强 C不是削弱 我认为C的结论有两种可能性(C) Recently discovered samples of the vaccine dating from 1960 still show traces of the virus 可能是病毒本身就是vaccine产生的而不是vaccine was contaminated with the virus.  如果是这种情况呢？他都会发现病毒啊 所以无法支持结论

-- by 会员 sunjin1988 (2009/10/19 12:00:00)

jbc88

eshopaholic

可否把E看成结论的逆否命题

结论：vaccine contamination 导致 virus found in M

逆否命题：no virus found in M --- vaccine not contaminated

逆否命题成立，就是对结论的支持。