问题补充：
My bossfor Beijing in a few days. Do you know when his plane?
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：考查时态。现在进行时表示将来时，指按照计划安排要发生的事情，其动词是那些表示位置变化的动词；一般现在时表示将来时，指按照车站，机场的时刻表安排要发生的事情。本题的第一空是指安排好的要发生的事情。第二空指飞机按照时间表安排要起飞。故B正确。
