比较从句问题。。。

404.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) twice 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

为什么要有what? 前后对比的不都是rate么？

如果是In the 1980’s the rate of increase of the minority population of the United States was nearlytwice it was in the 1970's.
it指的就是 the rate ,前后比较的不就是the rate么？ what 指的又是什么，它不是多余么？。。。晕

问题2：
197.(27650-!-item-!-188;#058&002540)

(GWD-1-Q16)

Soaring television costs accounted for more than half the spending in the presidential campaign of 1992, a greater proportion than it was in any previous election.

A. a greater proportion than it was

B. a greater proportion than

C. a greater proportion than they have been

D. which is greater than was so

E. which is greater than it has been


prep对A的解释是，it指代的是a great proportion或the spending,都继承了a great proportion 或 the spending 发生在presidential campaign of 1992的特性，造成比较的逻辑关系错误。

对比prep198题


Between 1990 and 2000 the global economy grew more than it did during the 10,000 years from the beginning of agriculture to 1950.

A. Between 1990 and 2000 the global economy grew more than it did during the 10,000 years from the beginning of agriculture

B. Between 1990 and 2000 the growth of the global economy was more than that during 10,000 years, from when agriculture began

C. The growth of the global economy between 1990 and 2000 exceeds that which had been for 10,000 years from the beginning of agriculture

D. The growth of the global economy between 1990 and 2000 exceeds what it has been for 10,000 years, from when agriculture began

E. The growth of the global economy between 1990 and 2000 exceeded what it did for the 10,000 years from the beginning of agriculture

prep对这题的解释： it完全指代the global economy,并不特指1990到2000年之间的global economy。

这两个题中，怎么判断it 指代是不是特指？

问题3：
还是prep198
Between 1990 and 2000 the global economy grew more than it did during the 10,000 years from the beginning of agriculture to 1950.

A. Between 1990 and 2000 the global economy grew more than it did during the 10,000 years from the beginning of agriculture

B. Between 1990 and 2000 the growth of the global economy was more than that during 10,000 years, from when agriculture began

C. The growth of the global economy between 1990 and 2000 exceeds that which had been for 10,000 years from the beginning of agriculture

D. The growth of the global economy between 1990 and 2000 exceeds what it has been for 10,000 years, from when agriculture began

E. The growth of the global economy between 1990 and 2000 exceeded what it did for the 10,000 years from the beginning of agriculture


Between 1990 and 2000 the global economy grew more than it did during the 10,000 years from the beginning of agriculture to 1950
it did = the global economy grew. 所以 根据比较从句省略原则： 当比较从句的主语和谓语与从句的主语和谓语相同时，可以全部省略，常常保留作状语的介词短语或状语从句，那么此句是不是可以省略为Between 1990 and 2000 the global economy grew more than during the 10,000 years from the beginning of agriculture to 1950.

谢谢大家的解答

the rate cannot be fast (all four choices are out)


similar elimination can be found in prep07 #1







jjust look for the incorrect choices( they commit the same mistakes as the one you raised)


also , what is used here to introduce a structure


I don't know how should we call it , but it is a noun phrase


this question is not official source? isn't it ?

I'm not a big fan of this explanation


I think what is wrong is the first question is that it does not have any logical antecedent


to be more specific about your question  


the precise reference of it


I eat a apple ate by my mother, and it was ate by my father this afternoon (not a perfect example, but that is enough)


you use it , it here refers to a apple ate by my mother


it should refer to a noun ( included essential modifier) 。。。that is the point

nope


that would be hard for us to understand what is being compared