OG11-62，动词时态

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

正确答案选D。

OG的解释是：

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.

我怎么也想不通的是，既然agreement是1972年发生的，而且用一般过去时表示了它的动作reduced。agreement已经发生了reduced amount的作用，为啥那个dumping是持续到现在，要用现在时呢？

想不通啊想不通

看了gemj的大全，上边的标准答案居然选的是A???

到底哪个才是标准答案啊？

虽然我肯定偏向A。。。