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题库 / Prep2007E2-CR-24
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?
SV40 is widely used as a research tool in cancer laboratories.
Changes in the technique of manufacturing the vaccine now prevent contamination with SV40.
Recently discovered samples of the vaccine dating from 1960 still show traces of the virus.
In a small percentage of cases of mesothelioma, there is no history of exposure to asbestos.
In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40.
因此需要选择的选项是支持：（被污染的）疫苗是病毒的来源
E之所以正确，是因为：
在美国，组织中有病毒——疫苗被污染
在芬兰，组织中没病毒——疫苗没被污染
因此芬兰的情况证明了病毒是来源于被污染的疫苗的结论。
c只是单纯说了疫苗里有病毒，但是并不能说meso是因为疫苗被污染，然后有sv40导致的
削弱了
C：Vaccine was the source of the virus found in mesotheliom
C——现在也能找到被感染的vaccine，与题目给出的信息重叠了
E——芬兰Vaccine没感染，芬兰样本中没VIRUS。美国感染了，美国样本有virus。进一步加强了相关性
C和答案给出的信息一样，做不了增强的作用
且c是sample
∵一些疫苗被SV40污染
∴疫苗是SV40导致M病的源头
增强，即排除他因（CQ1）或加强因果链条（CQ2）
A、SV40是癌症实验室的常用工具，NM疫苗，无关
B、新技术让SV40不会污染疫苗了，未提M病，无关
C、最近发现的1960疫苗样本展现出病毒轨迹（什么疫苗、什么病毒，都没说清楚），无关
D、很少的M病没有接触A（那也不一定就接触疫苗了），无关
E、在疫苗没有被污染的地方，患M病的人体内不具有SV40，反因反果，加强相关CQ2，CORRECT
C still show traces of the virus.疫苗中仍然有病毒的痕迹 残留，
原文前提已经说了 however, in 1960 some polio vaccine was contaminated with the virus.病毒被感染了，
重复前提，没用，不能加强前提
说明where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40. 没有vaccine的地方就没有sv40，这个可以加强
C still show traces of the virus.疫苗中仍然有病毒的痕迹 残留，
原文前提已经说了 however, in 1960 some polio vaccine was contaminated with the virus.病毒被感染了，
重复前提，没用，不能加强前提
原文前提已经说了 however, in 1960 some polio vaccine was contaminated with the virus.病毒被感染了，
重复前提，没用，不能加强前提
P：in 1960 some polio vaccine was contaminated with the virus
C： this vaccine was the source of the virus found in mesotheliomas decades later
若想加强（取非），要么提到出现这个结果的另一个原因，要么讨论前提和结论中两件事儿的关系。
前面的论证 包括说SV40是contributing cause是已经没有问题的 相当于是fact
作者最后的论证结论是关于SV40的真正来源是不是那批被污染的疫苗
而不是什么SV到不导致cancer之类的
一定要抓住结论！！！！
C：这些被感染的疫苗导致了m癌症
A. 无关
B. 现在的技术可以使疫苗不被感染，不能说明癌症是由于之前感染的疫苗导致的
C. 最近发现的1960年代的疫苗里面还有猴子病毒。重复了前提，重复前提不能加强结论
D. 一小部分m癌症病例中没有接触过a。与前提无关
E. 在芬兰疫苗都没被污染，m癌症的样本中不含猴子病毒。因为非A，所以非B。加强结论