OG13 sc 77题

detective

77. A 1972 agreement between Canada and the United Statesreduced the amount of phosphates that municipalities had been allowed to dumpinto 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

C为啥是正确答案。OG说关于时态的问题，没看懂。

supervivian

1，1972年的协议，是一个客观存在，不涉及到过去，更不涉时间段。因

为题目不是“in 1972”，而是“a 1972 agreement” 。

2，用完成时一定要小心，尤其是过去完成时，这是个外国人都很少用到的

时态。所以要养成一个好习惯，那就是看到完成时就要找时间段。

希望能够帮到你