—Did you look up the time of trains to Shanghai?—Yes the early train is to leave at 5：30

问题补充：

—Did you look up the time of trains to Shanghai?

—Yes，the early train is to leave at 5：30 am.

A. likely

B. about

C. possible

D. due

答案：

A. likely

B. about

C. possible

(答案→)D. due

解析：考查固定句式。固定词组be likely to do sth可能做某事；be about to do sth马上就要做某事，与when连用；be due to do sth预定好了做某事；句意：—你有没有查一下去上海的火车时间表？—是的。最早的火车是在5点半就离开了。根据句意可知火车离开是事先预定好的事情，故D项正确。