问题补充：
Hurry! The plane . You know, it at 3:15.
A. takes off, takes off
B. is taking off, takes off
C. takes off, is taking off
D. is taking off, is taking off
答案：
A. takes off, takes off
(答案→)B. is taking off, takes off
C. takes off, is taking off
D. is taking off, is taking off
解析：
试题分析:考查动词时态。某些表示位置转移的词可以用现在进行时表示最近或较近的将来。从语境可知飞机马上就要起飞了，所以用is taking off；而按照时刻表规定的要发生的事情要用一般现在时表示将来，所以第二个空用takes off，故答案选B。句意：快点！飞机就要起飞了。你知道，飞机是3：15起飞。
