We were having evening class the light went out.A. whileB. even ifC. as if D. when

问题补充：

We were having evening class the light went out.

A. while

B. even if

C. as if

D. when

答案：

A. while

B. even if

C. as if

(答案→)D. when

解析：原句意思是，当灯熄灭的时候，我们正在上晚自习。While 然而，当……的时候（持续时间较长）；even if 即使； as if好像；when 当……时候，（侧重强调一个时间点）。所以选D。