问题描述:
since前到底是用过去式还是现在完成时?
Plasitic shopping bags______ no longer free at the supermarkets since June 1st,2008
A.were B.will be C.have been D.have
应该选哪一个?为什么?
这到底是为什么?
Plasitic shopping bags______ no longer free at the supermarkets since June 1st,2008
A.were B.will be C.have been D.have
应该选哪一个?为什么?
这到底是为什么?
问题解答:
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