求助一题 多谢

ypl214

People who have spent a lot of time in contact with animals often develop animal-induced allergies, some of them quite serious. In a survey of current employees in major zoos, about 30 percent had animal-induced allergies. Based on this sample, experts conclude that among members of the general population who have spent a similarly large amount of time in close contact with animals, the percentage with animal-induced allergies is not 30 percent but substantially more.
Which of the following, if true, provides the strongest grounds for the experts’ conclusion? （A）
A.    A zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation.
B.    A zoo employee is more likely than a person in the general population to keep one or more animal pets at home
C.    The percentage of the general population whose level of exposure to animals matches that of a zoo employee is quite small.
D.    Exposure to domestic pets is, on the whole, less likely to cause animal-induced allergy than exposure to many of the animals kept in zoos.
E.    Zoo employees seldom wear protective gear when they handle animals in their care.

spz316

给LZ说两种方法吧：
读题：
EVIDENCE: 动物园员工30%会染病
CONCLUSION: 总人口中超过30%会染病

简化模型：
EVIDENCE:   X——Z
CONCLUSION:    Y——Z
缺一个桥梁就是X----Y，你看看A选项是不是直接把X——Y搭上了桥  
X是动物园员工，Y是总人口


再来个直接的方法：
我们无非是想说，总人口要>30%
题目已知的是current动物园员工人口中是30%
A说的的是，生病的经常换工作，也就是说30%的被少算了，因为重病的就会换工作。

希望lz能明白吧

ypl214

恩  多谢了 明白了