What brought that on? - I don't know.

为什么会那样呢？ -我不知道。

I don't know. I mean, what brought that on?

我不知道，那是怎么回事呢？

Well, I thought I was dying. - Okay, what brought that on?

- 好吧，我以为我快死了。- 好吧， 是什么引起的？

I don't know. What, I mean, what brought that on?

我不知道，我是说为什么他会这么想呢？