问题补充:
---Listen! Someone is knocking at the door. Who it be?
---It be Tom. He phoned to visit me this evening.
A. may; may
B. may; shouldn’t
C. must; can
D. can; may
答案:
A. may; may
B. may; shouldn’t
C. must; can
(答案→)D. can; may
解析:考查情态动词用法。根据句意: ---听!有人正在敲门。可能会是谁了?----也许可能是Tom.他打过电话说今晚要拜访我。Can 表示可能性,故排除B和C。