1.—Who is the beautiful girl standing at the school gate?
—Well, if you ________ know, her name is Nancy.
A. may B. can
C. must D. shall
答案与解析：C 句意：——站在校门口的那个漂亮女孩是谁？——如果你一定要知道的话，她叫南希。此处的must表示“一定要，非要”的意思。
2．—When shall we meet your cousin at the station?
—His plane took off 2 hours ago, and it ________ reach at 5 p．m..
A. should B. could
C. must D. can
答案与解析：A should的意思是“应该会，可能”，在这里表示对将来的推测，“预期会……”。
