问题补充：
Hurry up! The train . You know it at 8:30 am.
A. leaves; leaves
B. is leaving; leaves
C. leaves; is leaving
D. is leaving; is leaving
答案：
A. leaves; leaves
(答案→)B. is leaving; leaves
C. leaves; is leaving
D. is leaving; is leaving
解析：考查时态。第一个，The train is leaving, 一般现在进行时表将来，意思为“火车马上就要离开了”。第二个,You know it leaves at 8:30. 这句里面是一般现在时，用来表示一个客观的状况，也就是火车8点半离开。
