单选题 Nobody noticed the thief slip into the house because the lights happened to ______.
A. be put up B. give in C. be turned on D. go out

【正确答案】 D
【答案解析】因为灯碰巧熄灭，没有人注意到小偷溜进房间。go out“熄灭，出去”；put up“举起”；give in“让步”；turn on“开(灯)”。