介词before 的意思包括: 在……之前(表时间)，在……前面(表位置)，比……重要(表程度)

1.作状语

They knelt before the throne.

他们跪在御座前。

She has lived there since before the war.

她从战前起就一直住在那里。

Something ought to have been done before now.

先前就应该采取措施了。

We will know before long.

我们很快就会知道了。

What you want to do is put before you.

你想要做的事情就摆在你的面前！

2.作定语

The year before last he won a gold medal, and the year before that he won a silver.

他年前得了一块金牌，大前年得了一块银牌。

The day before yestetday, we held am important meeting in our school.

前天，我们学校召开了一个重要的会议。

3.作表语

Before you is a list of the points we have to discuss.

放在你面前的是一份我们要讨论的要点清单！