Turn the light off as you go out.; Please switch off the lights when you leave.

出门时请随手关灯。

《新英汉大辞典》

The stop/start-enginenotifications could switch the engine off and on automatically, or they couldtrigger alerts to the driver to turn it off/on manually.

这种引擎开/关通知可以自动地在开启与关闭之间切换，或者该系统也可以给司机发送“戒备信号”让司机自己动手开启或关闭汽车引擎。

youdao

So every once in a while, turn off your phone and laptop, switch off the TV and lay your worries temporarily to the side.

因此不妨偶尔关掉你的电话，电脑和电视，把烦恼暂时放在一边，和自己（或是你的同伴）约个会， 至少完整的

youdao

Of course, to turn the on-off switch on is harder when somebody's in a coma.

当然要开启这个开关难度更大,当人陷入昏迷。

耶鲁公开课 - 死亡课程节选

You don't need a light switch or a light bulb or an iPhone app to turn something on or off.

你不需要一个电灯开关,或者一个电管,或者打开关闭一个iPhone应用程序。

哈佛公开课 - 计算机科学课程节选

With no hard drive, and a switch to turn off the wireless connection (not the fastest in the world), power can be conserved.

ECONOMIST: Rational consumer

As you pass a major landmark, your phone may switch off your music and turn on an audio recording of a person describing a landmark you're passing.

BBC: Five favourite travel apps of 2011

Users can turn Lykka off or switch to a different avatar if they like.

CNN: Review: MacSpeech demos voice recognition