有一个问题一直弄不懂，请大家指教！

我对这个问题也很迷茫，看下面两个题目：    

Because natural gas is composed mostly of methane, a simple hydrocarbon, vehicles powered by natural gas emit less of certain pollutants than the burning of gasoline or diesel fuel.

(A) less of certain pollutants than the burning of gasoline or diesel fuel

(B) fewer of certain pollutants than burning gasoline or diesel fuel do

(C) less of certain pollutants than gasoline or diesel fuel

(D) fewer of certain pollutants than does burning gasoline or diesel fuel

(E) less of certain pollutants than those burning gasoline or diesel fuel

答案是E

    The United States government employs a much larger proportion of women in trade negotiations
than any

government.

(A) a much larger proportion of women in trade negotiations than any

(B) a much larger proportion of women in trade negotiations than does any other

(C) much larger proportions of women in trade negotiations than has any

(D) proportions of women in trade negotiations that are much larger than any

(E) proportions of women in trade negotiations that are much larger than any other

答案是B

为什么说第一个就是比较实体，不补助动词，第二个就要，他们有什么区别吗？

如果第一题的E改成 less of certain pollutants than do those burning gasoline or diesel fuel，对吗？

如果第二个的B改成a much larger proportion of women in trade negotiations than any other,对吗？

盼望得到澄清，谢谢！

比较主语（名词）的时候，比较的谓语动词省略：fficeffice" />

其实很简单，首先不引起歧义，然后简洁。

As前面是只有主语+动词词组+不是名词的任何东东，as后面的谓语可以省略，为了简洁，而且不会引起歧义。

As前面是有主语+动词词组+带有名词词组的东东（宾语，名词表语，谓语中介词宾语等等），为了避免歧义，as后必须加谓语助动词，as后的从句可以倒装。不加的话，as后的名词可能会对应到别的名词。