GWD7-5 老题新问了。。。

Exposure
to certain chemicals commonly used in elementary schools as cleaners or
pesticides causes allergic reactions in some children.  Elementary school nurses in Renston report
that the proportion of schoolchildren sent to them for treatment of allergic
reactions to those chemicals has increased significantly over the past ten
years.  Therefore, either Renston’s schoolchildren
have been exposed to greater quantities of the chemicals, or they are more
sensitive to them than schoolchildren were ten years ago.

Which of
the following is an assumption on which the argument depends?

A.   
The number of school nurses employed by
Renston’s elementary schools has not decreased over the past ten years.

B.   
Children who are allergic to the chemicals
are no more likely than other children to have allergies to other substances.

C.   
Children who have allergic reactions to the
chemicals are not more likely to be sent to a school nurse now than they were
ten years ago.

D.   
The chemicals are not commonly used as
cleaners or pesticides in houses and apartment buildings in Renston.

E.    
Children attending elementary school do not
make up a larger proportion of Renston’s population now than they did ten years
ago.

答案选C没有问题 只是我还是想不通E为什么不行。。。 之前好多人问了D的问题。。。 可是我选的是E

把E取非 就是现在进入那个学校的学生比10年前多了 是不是也会增加学生被送去护士那里的几率呢 毕竟林子大了什么鸟都有了嘛

这样就削弱了本题的结论是由于have been exposed to
greater quantities of the chemicals, or they are more sensitive to them

还望赐教。。。

我觉得学生多了推不出得这个病学生的比例就多了，如果这十年来学生得这个病的概率没有升高，不管进来多少个学生，得病学生的比率是不变的，你选这个E的时候unfairly assumes that children are more likely to be allergic to the disease than previously.

另外学生占总人口比例增加也可能是总人口下降导致的，不一定学生数量增加，总之E说的很不直接，而且单单从数量上是不能驳斥rate变化的原因。