---Listen! Someone is knocking at the door. Who it be?---It be Tom. He phoned to visit me

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。