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
that引导宾语从句,在从句中只起连接作用,不作任何成分,常被省略,但当谓语后接两个或两个以上宾语从句时,第一个that可以省略,第二个that不能省略。故选B项。why引导宾语从句意为“为什么”。when引导宾语从句，意为“当……的时候”。where引导宾语从句意为“在……地方”。