问题补充：
If you be in time for the early bus , be sure to get up before five o’clock in the morning.
A. are to
B. are about to
C. are going to
D. are due to
答案：
(答案→)A. are to
B. are about to
C. are going to
D. are due to
解析：考查将来时的表达法。Be to do sth表示将来时的时候，表示一种语气，非要做某事，相当于must，be sure to do sth；be about to do sth即将做某事，不与具体的将来时的时间状语连用；be going to do sth表示计划好要做某事，或者根据某种迹象要做某事；be due to do sth表示预定好了要做某事；句意：如果你一定要赶上早班公交车，务必要在5点之前就起床。故A正确。
