gwd-7-5

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?

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


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


3. 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.


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


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

answer is  C, but i can't figure out the difference between B and C.

pls let me know.

B and C are clearly different.

B is not relevant to the original argument.

C, on the other hand, is an assumption of the original argument.  Try deny C, we get "Children who have allergic reactions to the chemicals are more likely to be sent to a school nurse now than they were ten years ago."  If so, this could have caused most of the reported increase by nurses, and the original argument that "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" would fall apart.  So, C is an assuption, and the best answer.

i got it!

B is relevent or out of scope,  C is best.

but little confused with "no mare likely"  in B and "not more likely" in C.

thanks!

A：护士多少跟有多少学生送过去没有关系，不会说今年护士少了，学生们有过敏的就克制一下吧

B：我觉得是两个无关比较；其他学生以及其他过敏都无关，有关系的是十年前与现在

C：取非削弱

D：在家里和公寓里，无关

E：比较的是学校内部的比例，如果结论是在整个城市中过敏的病人中，现在过敏的小学生比十年前的比例升高了，那么E是一个正确选项

我觉得E错误不是像5楼说的：E比较的是学校内部的比例，原文讲的是Elementary school nurses in Renston repots that..., 说的就是在Renston地区的小学，而E的意思是说在Renston地区上小学的人数并不比10年前所占人口的比例大，问题在于E说的是一个比例，而不是一个绝对数，有可能现在总的地区人口数下降，而上小学的人数不变，可所占总人口数的比例还增高了（如E）,

我觉得如果E说的是现在上小学的人数不比10年前上小学的人数多，则也是一个取非削弱。

E的错误是把比例当成了绝对数

我還是不懂...為何b取非可以削弱??我怎麼看都是支持啊?

make sense

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.  

我觉得B错的关键是对题干所给条件的反驳,这种答案通常是不能作为ASSUMPTION的.

因为这题我也错选了B,回过头再看的时候才发现这个问题.不知NN们以为如何?