— Is your brother afraid of the dark?— Yes. He always goes to sleep with the bedroom light

— Is your brother afraid of the dark?
— Yes. He always goes to sleep with the bedroom light .
A. off
B. in
C. at
D. on

A. offB. inC. at(答案→)D. on解析：off离开，切断；in在里面；at在一点；on在上面，开着的。句意：你的弟弟怕黑吗？——是的，他总是开着卧室的灯睡觉。故选D。

好好学习下