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。句意：快点！火车就要开了。你知道的，火车上午8:30开。火车将要开动，是将来时，表示位置移动的词go, come, leave, move等，可以用进行时表示将来，排除A、C；按照时刻表上规定好的时间做某事，用一般现在时，排除D。故选B。
