He hasn,t heard from his frend______last month.A.since B.by the end of C.must 知道怎么做的告诉下,要理由

问题描述:

He hasn,t heard from his frend______last month.A.since B.by the end of C.must
知道怎么做的告诉下,要理由

A
现在完成时后跟时间点的话用for