单选题 ______ the students had to go to bed
A. The lights had gone out B. The lights having gone out
C. The lights went out D. The lights have gone out

【正确答案】 B

【答案解析】[解析] 灯灭了，学生们必须上床睡觉。
[考点] 独立主格结构
[解析] 前后两个句子主语不一致。现在分词有自己的逻辑主语the lights，属于独立主格结构。因此前半句要用现在分词形式。故选B。