工作人员在兑现支票前先把它复印了。

Staff photocopied the cheque before cashing it.

《柯林斯英汉双解大词典》

我想在来这里追寻我的音乐之前先把学业解决了。

I wanted to get my academic work settled before pursuing my music here.

youdao

使用浴盆前先把里面擦洗干净。

The bath before you use it.

youdao

c We know it's very specific for light because in this equation is c, the speed of light. So any time you go to use this equation, if you're trying to use it for an electron, just ask yourself first, does an electron travel at the speed of light?

我们知道它只对光适用是因为在这个方程里有,光速，所以下次你们用这个方程前，如果你们要把它用到一个电子上，先问问你自己，电子的运动速度是光速吗？

麻省理工公开课 - 化学原理课程节选