过了很长的时间，他们才弄明白问题的所在。

It was some time before they work out what the problem was.

youdao

您疯狂地试图弄明白问题所在，以便可以按时驾车去上班。

You frantically try to figure out the problem, so you can get to work on time.

youdao

You get clear about the kinds of questions we've just been asking about the badness of death, whatever that is.

你弄明白我们所问的关于死亡的坏处的,这类问题，不管是什么。

耶鲁公开课 - 死亡课程节选

So exam this and be sure you understand that.

因此请仔细思考这个问题并确保弄明白。

麻省理工公开课 - 热力学与动力学课程节选