问题
选择题
Having checked the doors were closed, and _____all the lights were off, the boy opened the door to his bedroom.
A．why
B．that
C．when
D．where
答案
答案：B
本题考查宾语从句的连接代词。that 引导的宾语从句，若有两个或两个以上，只有第一个that可以省略。Having checked the doors were closed中省略了that。
【标签】名词性从句