feifei-114

114. The number of North American children who are obese-that is, who have more body fat than do 85 percent of North American children their age---is steadily increasing, according to four major studies conducted over the past 15 years.

If the finding reported above is correct, it can be properly concluded that

A.        when four majors studies all produce similar results, those studies must be accurate

B.        North American children have been progressively less physically active over the past 15 years

C.        the number of North American children who are not obese increased over the past 15 years

D.       over the past 15 years, the number of North American children who are underweight has declined

E.        the incidence of obesity in North American children tends to increase as the children grow older

答案：C

思路： 先看选项做分析

A.        归纳太偏。

B.         文中没有提到。

C.         正确，理解思路是obese是一个比例，不是具体的数据，即15％，如果obese的人数增长，说明children的总人数增加，因此本答案正确，个人认为本题不是一个好题目，但是有可能是一个类型题目的代表，相当于a占整体的一个固定比例，b占整体的一个固定比例，a和b不一定加起来就是整体，根据a数据的变化推断b数据的变化。

D.        易混淆，出现新名词underweight，文中没有提到。

E.         无关。

我的问题是：为什么原文是讲.       “ the number of North American children who are not obese increased over the past 15 years ”，  但解释是讲总人数增加，还没解释到为什么not obese的人增加，这到底如何解释？

我觉得 文中讲obese是有体脂肪超过85%同年小孩有的体脂肪

即obese=15%  not obese=85% 这比例是不会变的

既然obese总数增加了 那not obese总数也增加了