大全987-2答案是不是搞错了

1.        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（A）

(E) reduces the amount of phosphates allowed for dumping by municipalities

虽然大全上面写的答案是A，但是OG11上面给的答案是D，给出的解释如下：

The past tense reduced is correctly used in this sentence to describe a past action, and the present tense are allowed is used to decribe the present situation.

我当时做OG的时候，选择的答案就是A，后来看了答案和解释百思不得其解。虽然硬说也说得通，但是总觉得不如A好。

请哪位大牛赐教，是OG错了，还是大全错了？

谢谢！

以OG为准。

已经倒出的量怎么可以减少呢对不？

刚看到这题，感觉和你一样，选A，但仔细想想A是错的，我们的思维主要受到这句话中文翻译的影响：‘法规使以前被允许倾倒的P的数量减少了’，但实际这句话要告诉我们的是通过1972年的法规，‘从那以后允许倾倒的P的数量减少了’，这才是法规的真正作用，就如everMM说的，已经过去的事情法规是起不了作用的，文中除了1972之外没有其它时间状语，因此可以理解为这个法规的影响一直延续到现在，所以应该用一般时。

太精辟了：“实际这句话要告诉我们的是通过1972年的法规，‘从那以后允许倾倒的P的数量减少了’，这才是法规的真正作用”

感谢tiantian8273

！