Prep 中的一道SC，请大家指点一下

glacier超

Providing initial evidence that airports are a large source of pollution than they were once believed to be, environmentalists in Chicago report that the total amounts of pollution emitted annually by vehicles at O`Have International Airport is twice as much as that which is being emitted annually by all motor vehicles in the Chicago metropolitan area.

A   as much as that which is being emitted annually by all
B   as much annually as is emitted by the
C   as much compared to what is annually emitted by all
D   that emitted annually by all
E   that emitted annually compared to the

大家分析一下这个题目，答案是D。为什么是这个选项呢？

jujurenee

凭语感首先能排除B，这个应该没有疑问。A‘that’接‘which’，显然是一个十分混乱的从句结构。c “as much as' 不完整。E 'twice'的用法有: twice as many...as; twice as much...as; twice+the+n; twice +what从句；twice+that 从句；twice这里本身就是比较的意思了，没有必要后面再加一个compared to所以选D更好。

红尘道士

这道题考的是twice和as 。。。as的用法，that指代the total amounts of pollution 是正确答案的标志，排除B，C
A中that指代+which指代，重复了
E中copared to 比较无意义，同时twice比较+compared to比较啰嗦，不简洁

本题中还有个知识点the total amounts of pollution 中心词是pollution，而不是ammounts，要注意，不然就应该用those指代了