问题描述：
---Have you ever smoked?
---Yes,but it’s three months since I ____.
A.smoked B.have smoked C.didn’t smoke D.haven’t smoked
请问答案为什么选A,而不选C?
---Yes,but it’s three months since I ____.
A.smoked B.have smoked C.didn’t smoke D.haven’t smoked
请问答案为什么选A,而不选C?
问题解答：
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