He could turn off a light and then jump into his bed before the room got dark.

VOA: special.2009.01.24

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

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