He fell asleep with the light off.

灯关掉的状态下，他睡熟了。

youdao

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》

Please join us to light off firecrackers.

让我们一起来燃放爆竹除旧岁。

youdao

They used light-sensitive molecules to turn on and off nerve cells in the deep brain structure of mice.

VOA: special.2009.04.07

And instead of having the electron giving off energy as a photon, instead now the electron is going to take in energy from light and move up to that higher level.

与电子以光子形式施放能量不同,我们现在要从光中,获得能量到一个更高的能级。

麻省理工公开课 - 化学原理课程节选

And if we do, in fact, hit it with light to get the electrons off, it will go back to the straight up in position, or if it gets knocked hard enough it does that, too.

而且如果我们这么做，事实上，用光轰击它以逐出电子，它就会在原位置沿直线返回，或者如果它被撞击的足够猛烈,也会出现上述现象。

麻省理工公开课 - 化学原理课程节选

It uses a small spectrometer to bounce infrared light off particles in the sample.

ECONOMIST: Anti-IED technologies

Changes in the ions' vibration rate were measured by bouncing laser light off them.

ECONOMIST: Scientists measure a few yoctonewtons for the first time

We bounce light off of visible parts into hidden parts and then measure the time and direction of returned light.

CNN: A camera that can see around corners