比较题里it的指代问题

goodbaby102

有两个比较题，我搞不太明白，是关于it的指代，一个是不可以用的，一个是可以的，有点糊涂，题目如下：

1，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       (B)

E.        which is greater than it has been
答案是B，为什么不能是A呢，A里的It可以指代proportion吗？

2，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         (A)

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
这题答案是A，it指代global economy

为什么一个可以用it，一个不可以用it啊

兰心寒

http://forum.chasedream.com/thread-784791-1-1.html

haiyueqinhui

第二题：
这里是同义同物，所以可以用it

haiyueqinhui

第一题：
more than half the spending in the presidential campaign of 1992, a greater proportion than it was in any previous election.
好麻烦的句子，简约下：
half the spending in A campaign, a greater proportion than it was in any previous election.

首先是比较结构前后不对等，前面没有谓语动词，怎么就冒出来was呢？
其次是it，it只能指代同义同物，同义它物是that;
因为前后有 in the presidential campaign of 1992意思与结构的相呼应 in any previous election，去掉that不会构成句意不清晰，所以去掉that是可以的——这不就是我们的B选项么！