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题库 / OG13-SC-77
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.
reduced the amount of phosphates that municipalities had been allowed to dump
reduced the phosphate amount that municipalities had been dumping
reduces the phosphate amount municipalities have been allowed to dump
reduced the amount of phosphates that municipalities are allowed to dump
reduces the amount of phosphates allowed for dumping by municipalities
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老师，请问AC为什么不对？完成时表示时间更往前，那么就是reduce了原来规定的量，我当时觉得这样是正确的。求解答
这个是过去一个特定时间里发生的事情，所以reduce是要用过去式的；
而，从句是在叙述一件客观存在的事实，所以用一般现在时。
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