问题
选择题
---- What was wrong with you yesterday evening?
---- I ____ my homework when the light went off suddenly.
A．doing
B．was doing
C．did
D．have done
答案
答案：B
考查情景交际。“昨晚你怎么了？”“我正在做作业时，突然断电了。”过去某时刻正在发生的事情用过去进行时。故选B。