og11的62题

OG解释中是选了D，但我看大全与刘振民里对这道题都是选A，对于这道题中时态的用法到底应该如何？

OG解释：

A 1972 agreement between Canada and the United States
    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

Verb form + Idiom

An agreement that occurred in 1972 is correctly described with the past tense verb reduced. Since the dumping continues into the present, the past perfect verb had been allowed should instead be the present are allowed.

A     Had been allowed should be are allowed

B     The phosphate amount should be the amount of phosphates; the meaning of the sentence is changed by the omission of any form of allow

C     The present tense reduces should be the past tense reduced; the phosphate amount should be the amount of phosphates; have been allowed should be are allowed

D     Correct. 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.

E      The present tense reduces should be the past tense reduced; allowed for dumping is an incorrect idiom; allowed for dumping by municipalities is awkward

The correct answer is D.

感觉还是以OG为主吧。

翻译：1972年加拿大和美国之间的一个协议减少了磷酸盐排放的总量，这些地方是允许往湖中排放磷酸盐的。

减少是在72年发生的，用过去时。允许是一直客观存在的，用现在时。所以选D。

为什么不选A？减少不是禁止，所以1972年以后人们仍然在放磷酸盐。如果用过去完成时的话意思就变成在1972年之前允许，之后不允许，前后矛盾。

谢谢！