— I am going to the dentist at 4 o'clock and it is 3：30 now.— Well if you leave earlier

问题补充：

— I am going to the dentist at 4 oclock and it is 3：30 now.

— Well, if you leave earlier today, please ask the director for permission.

A. can

B. may

C. must

D. will

答案：

A. can

B. may

(答案→)C. must

D. will

解析：考查情态动词。must在这里是“偏要”的意思。故选C。