问题补充:
Before you leave the classroom, please the lights.
A. turn up
B. turn down
C. turn on
D. turn off
答案:
A. turn up
B. turn down
C. turn on
(答案→)D. turn off
解析:此题重点考查四个短语的区别,turn up出现,开大;turn down 减小,关掉;turn on 打开; turn off关掉。句意:在你离开房间之前,请把灯关掉。结合语境可知选D。