GWD1-16

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.

多谢！脑袋不行了，我还把它当动词第三人称呢，咳，就这水平，还咋更ETS玩啊，路漫漫，且修远兮。。。。

But fro C. The tense is not correct. "accounted" and "they have".

So maybe the correct answer it B.

我也选了A说，

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

我倾向于选B，A选项it错误指代相同的propoation，C时态错误且they的指代我认为也是不对的。

B正确，a greater proportion than that was in...； 

A项错误还在于补出的助动词was错误，前面主句的动词是 accounted ，再怎么样也要补出did吧