学帮网the company has been producing this model of machine tool( )2008.A.since B.after C.fpr D.before
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the company has been producing this model of machine tool( )2008.
A.since B.after C.fpr D.before
A
现在完成进行时,表示从过去某个时间点开始进行、并将继续进行下去的情况,时间多用since.