Question

—How was that?
—I was chatting on line _____ the power went out.

A．because

B．while

C．as

D．when

Answer 1

D

试题分析：考查情景交际和从句连接词。--发生了什么事？--我正在网上聊天，这时（突然）断电了。。A因为；B当，常与进行时连用；C当，前后常加短动作；D当，那时（突然）。when在此表示“突然发生”，故选D。