问题补充：
I Beijing in a few days. Do you know when the earliest plant ?
A. leaves for; takes off
B. am leaving for;is taking off
C. am leaving for; takes off
D. leave for; taking off
答案：
A. leaves for; takes off
B. am leaving for;is taking off
(答案→)C. am leaving for; takes off
D. leave for; taking off
解析：考查时态，第一空是现在进行时态表示将来，现在进行时态有安排或打算(这种打算不固定)的含义时，表示最近或较近的将来。 第二空是一般现在时态表示将来，将来的事情已安排好且不轻易改变用一般现在时态表示将来。句意是我近几天打算去北京，你知道最早的航班是什么时候吗？故选C。
