白勇一道题 关于比较级的用法

zoechou11

In the 1980's the rate of increase of the minority population of the United States was nearly twice as fast as the 1970's

A twcie as fast as

B twice as fast as it was in

C twice what it was in

D two times faster than that of

E two times greater than

我想问为什么选C不选B呢， B不是一个没有省略的方式么，It指代the rate of increase...

解释说这是一个句子不能与前面主句（一个名词）比较，但是 我们很多题都是从句都是

一个句子的，例如 The guiding principles of the tax plan released by the Treasury

Department could have even a greater significance for the economy than do the

particulars of the plan.为什么这里这个do不省略。

什么时候从句的谓语不能省要是一个句子，什么时候从句要是一个名词性从句呢？

lisaluan

The guiding principles could have even a greater significance for the economy than do （could）the particulars of the plan。这句话不知道是哪的了，觉得不应该省略情态动词could啊，可能因为倒装？？？

In the 1980's the rate （of increase of the minority population of the United States） was nearly twice as fast as the 1970's

个人感觉
B twice as fast（increase） as it（rate） was in ，rate 不能用fast来形容

C twice what it （rate）was in ，rate 是两倍

所有
sth of sth，of都可以扩上，虽然意思有变化但逻辑还是正确的