英语语法 turn on/over/down/to 的各自的用法

turn on: 打开（电器之类的）
例如：Turn on the radio,please.
turn over: 翻转
例外：If you turn the box over, you'll see some words at the bottom of it.
turn down: 关小（电器之类的）声音
例如：Turn down the TV,please.Dad is sleeping now.
turn to:向某人求助
例如：He turn to his best friend for help.

36. turn 一般用法： in turn; by turns; turn on/off/down/up/in/to/out/over/round
特殊注意： 当turn用作系动词时，后面的名词前不加冠词，如：After years of hard work, he turned writer.

楼上的说的都对