问题补充:
——Who is knocking at the door?
——It Mr. Black, because heWashington.
A. can be;has gone to
B. may be;has been to
C. must’t be;has gone to
D. may be;went
答案:
(答案→)A. can be;has gone to
B. may be;has been to
C. must’t be;has gone to
D. may be;went
解析:句意:谁在敲门?不可能是布莱克先生。因为他已经去华盛顿了。can’t be意为“不可能是”,是对事情的否定推测,has gone to sp意为“已经去了某地还没有回来”;has been to sp意为“去过某地已经回来了”;故选A。