I while reading the English textbook. Luckily, my roommate woke me up in time!
A. had fallen asleep
B. have fallen asleep
C. fell asleep
D. fall asleep
网友回答
A. had fallen asleep
B. have fallen asleep
(答案→)C. fell asleep
D. fall asleep
解析：考查时态题。句意：当我正在读英语课本时，我睡着了。幸运的是，我的室友及时叫醒了我。结合语境可知主语描述的是过去某事发生的动作，故用一般过去时态。故选C。