大全885，Section 1，#23

23.   In 1980 the United States exported twice as much of its national output of goods as they had in 1970.

(A) twice as much of its national output of goods as they had

(B) double the amount of their national output of goods as they did

(C) twice as much of its national output of goods as it did

(D) double the amount of its national output of goods as it has（C）

(E) twice as much of their national output of goods as they had

比较之下也只能选C，但是觉的C中的时态也不太好，比较从句是否该用过去完成时态，毕竟1970相对1980是过去的过去。如果该用过去完成如何表达？twice as much of its national output of goods as it had(不用把exported加上吧？)

先谢谢大家帮忙指点！

找到白勇语法上的一道题目，第7章，209页，第36题。

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

答案选C，这题比较的也是1980和1970，比较从句用的也是过去时态，没有完成时态的选项，所以当时也就没有考虑时态的问题。

但是现在想来想去LZ说的也有一定道理！

请问NN这2题目为什么不用过去完成时态，明明是过去和过去的过去在比较呀！

又找到一个题目

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.

1. a greater proportion than it was


2. a greater proportion than


3. a greater proportion than they have been


4. which is greater than was so


5. which is greater than it has been

这是GWD-1的16题，大家谈论的结果是B，因为A的时态不对，该用过去完成时态。请问这题目和上面2题目有什么不同？时态现在弄的我头大了！

大家帮帮我吧！

顶呀！

这个时态问题到底如何解决呢？

大家来谈论谈论吧，万一考试出了这种东西呢？