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
题目分析：是一个1972年的agreement，应该用过去时，干掉C和E。语意上强调的是减少我允许你倾倒的量，不能没有allow这个意思，干掉B。A和D一个用过去完成一个用一般现在，法律法规规定的事情应该用一般现在时，选D
