请问大全164题？

xiaozi1357

但我不太明白为啥一定要是those？

Clear412

Mark一下！               

洛阳洋洋999

顶

inoooooo

GMAT FORUM里查了原题，gmat ninja回复如下：
First, you're right, the juiciest decision point is between "less" and "fewer." As is usually the case, the choice comes down to context and meaning. If we're talking about the number of pollutants emitted, we'd use "fewer" as this would be countable. If we're talking about the quantity of pollutants, we'd use "less" as the quantity of a volume isn't really countable. (A good rule of thumb here is whether the item in question can be expressed as an integer value. We can count to 3. But it doesn't make sense to count to 3.7.) Much more on countable vs. non-countable modifiers in this video.

Here it seems more logical to talk about the quantity of "certain pollutants." If one vehicle emitted four kinds of pollutants and another three kinds, it's not clear if we should care. It would really depend on how much was emitted. Also, if we were talking about the number of pollutants, it would be far simpler to just writer "fewer pollutants," as opposed to "fewer of certain pollutants." Because we'd prefer "less," to indicate a non-countable quantity, (B) and (D) are out.
这样就比较清楚了。
1、如果我们讨论有多少种pollutants被排放，用fewer，因为修饰可数；
2、如果我们想说污染物的量，那么用less，因为不能被表达成一个具体的数字。这里讨论的是排放量的问题，所以用less。
3、如果是想讨论pollutant的数量，那么只用说fewer pollutants即可，不要fewer of。
Ron说过，很多rule不是机械地去apply，比如下面的那些rules。首先我们要先明白这个句子到底想要表达什么，其次才是各种方法。
查了很久，供大家参考