马上考试了，可是有一个点没有弄懂啊，求NN指教。如下，我觉得下面两道题有点矛盾：
29. Although exposure to asbestos is the primarycause of mesothelioma, a slow-developing cancer, researchers believe thatinfection by the SV40 virus is a contributing cause, since in the United States60 percent of tissue samples from mesotheliomas, but none from healthy tissue,contain SV40. SV40 is a monkey virus; however, in 1960 some polio vaccine wascontaminated with the virus. Researchers hypothesize that this vaccine was thesource of the virus found in mesotheliomas decades later.
Which of the following, if true, most stronglysupports the researchers' hypothesis? C．Recentlydiscovered samples of the vaccine dating from 1960 still show traces of thevirus. （conclusion:vaccine里面的virus就是mesotheliomas里面找到的virus.B选项只能说明vaccine里面有virus这个已知前提，而不能证明这个virus就是mestheliomas里面的virus） D.In Finland, where the polio vaccinewas never contaminated, samples from mesotheliomas do not contain SV40. （正确答案）
20. Several ancientGreek texts provide accounts of people being poisoned by honey that textssuggest was made from the nectar of rhododendron oroleander plants. Honey made from such nectar can cause the effects the textsdescribe, but only if eaten fresh, since the honey loses its toxicity within afew weeks of being made. In Greece,rhododendrons and oleander bloom only in springtime, when they are thepredominant sources of nectar. B.In areas where neitherrhododendrons nor oleanders grow, honey is never poisonous. (光否命题不能证明，要逆否命题才行。这里还是不能证明中毒的都是吃了那种蜂蜜的)
D.Theincidents of honey poisoning that are related in the ancient texts occurred inthe springtime or in the early summer
我个人觉得29的正确选项D和20题的错误选项B都是一种support的方法，可是怎么一个正确一个错误呢，求指教啦！感谢！
| 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2015-9-20 11:01:12
收藏
收藏
楼主
