问题补充：
—Lin Kai, hand in your homework, please.
—Oh, sorry. I it at home this morning.
A. was leaving
B. has left
C. will leave
D. left
答案：
A. was leaving
B. has left
C. will leave
(答案→)D. left
解析：考查点：考查时态。解题思路：根据句中时间状语this morning表示过去的时间，可知用一般过去时态。故选D。
