I'm sure it happened before.

我确信这曾经发生过。

youdao

What happened before that?

在这之前发生了什么？

youdao

It's not like this hasn't happened before.

这不是以前没有发生过的。

youdao

"I will admit to having the breakfast-for-dinner kind of thing, that's happened before.

VOA: special.2010.11.22

I find that every time we do our meditation on Thursday, I'm always running to make it, or something happened before I get there, I'm like "Oh my God, meditation!"

我发现每次我们周四,要冥想时，我总是匆匆赶过去，或者是到达之前发生一点事故，我就好像“天哪，要冥想！“

普林斯顿公开课 - 人性课程节选

And what happened before it.

以及在这之前发生的事情。

That's why 课堂 - SpeakingMax英语口语达人

It has happened before under more dire circumstances, after the herd all headed for the exit.

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It quickly became apparent that I was having an asthmatic attack, which had never happened before.

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Whatever the reason, it happened before the earliest Stuxnet sample was discovered (June, 2009).

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