before的时态是什么样的

before是表示过去，应用于过去完成时态。

before：

prep.之前;在…以前;在…面前(或前面);(次序或排列)在前面。

conj.在…以前;到…为止;到…之前;以免;不然。

adv.以前;过去;已经。

扩展资料

I'd like a second opinion before I make a decision.

我在作决定之前，想听听别人的意见。

I didn't have time to change clothes before the party.

我没时间在聚会前更换衣服。

It would be a good idea to call before we leave.

我们出发之前打个电话是个好主意。

Profits were at the same level as the year before.

利润和前一年的持平。

Have you ever used this software before?

你以前用过这种软件吗？