[求助]请教一条OG上的语法题

swycielo

黄皮书P647页第62题：

A 1972 agreement between Canada and the United Stated reduced the amount of phosphates that municipalities had been allowed to dump into the Great Lakes.

A: reduced the amount of phosphates that municipalities had been allowed to dump

B: reduced the phosphate amount that municipalities had been dumping

C: reduces the phosphate amount municipalities have been allowed to dump

D: reduced the amount of phosphates that municipalities are allowed to dump

E: reduces the amount of phosphates allowed for dumping by municipalities

 

答案说选D: The past tense reduced is correctly used in this sentence to describe a past action, and the present tense are allowed is used to describe the present situation.可是我不太明白为什么要用present tense，觉得A选项比较合理。哪位好心人给我指点下，谢谢！

Colx

http://forum.chasedream.com/dispbbs.asp?BoardID=23&replyID=1416001&id=151571&skin=0

一切以OG为准

swycielo

看了那个帖子，我更加疑惑了...说不定答案本身就是错的...