问题补充：
Mr. Black Shanghai in a few days. Do you know when the earliest plane on Sunday.
A. leaves; takes off
B. is leaving; takes off
C. is leaving; is taking off
D. leaves; is taking off
答案：
A. leaves; takes off
(答案→)B. is leaving; takes off
C. is leaving; is taking off
D. leaves; is taking off
解析：考察将来时的表达法。本题第一空用现在进行时表示将来时，现在进行时表示一般将来时，表示按照计划安排要发生的事情，且动词要是一些表示位置变化的动词。句中的动词是leave也是表示位置变化的动词。第二空用一般现在时代替将来时，指按照机场，车站的时刻表安排要发生的事情。故B正确。
