Question

In our company,great changes____since the new manager came.

A.took place B.take place C.will have taken place D.have taken place选什么，为什么

Answer 1

D.have taken place

since要和现在完成时连用

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追问

是不是句子中出现since都要用现在完成时？

追答

It....since... 句型中常用一般现在时代替现在完成时（例外）
It is (has been) two years since he came here.

Answer 2

D
现在完成时，因为有since 引导的时间短语。