27.He hasn’t heard from his friend __________ last month.

问题描述:

27.He hasn’t heard from his friend __________ last month.
A.since
B.by the end of C.for
D.until
别误导人

A“自从上个月以来,他还一直没有收到他朋友的来信呢”since “自从...以来”,要求前面的主句用现在完成时.by the end of ...到...末为止,by the end of last month 只能用于过去完成时.for 后面必须接一段时间,而 la...