问题补充：
I while watching the movie last night. Unluckily, my roommate woke me up.
A. had fallen asleep
B. have fallen asleep
C. fell asleep
D. fall asleep
答案：
A. had fallen asleep
B. have fallen asleep
(答案→)C. fell asleep
D. fall asleep
解析：考查时态.根据时间状语last night可知描述的是过去发生的动作,故用过去时态,选C.
