标题: 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 [打印本页] 作者: alicejingli 时间: 2010-12-14 17:35 标题: 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 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？作者: jessiecg 时间: 2010-12-14 20:34
C只是重复原文吧，并没有加强假设啊。。作者: cdwayne 时间: 2010-12-15 11:50
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")