A policeman saw what was going on.

一名警察看到了发生的事情。

Then his jaw (下巴) dropped open and he laughed for joy as he realized what was going on.

然后，当他意识到发生了什么事时，他张大了嘴巴，开心地大笑起来。

If that was indeed what was going on.

如果那是真的，会发生什么事呢。

I really didn't know what was going on.

我完全不知道到底发生了什么。

The next step -- ask him what was going on.

下一步----问他到底发生了什么事情。

So what was going on in September of 2017?

那么2017年九9月发生了什么呢？

So, emma, what was going on in that video?

艾玛，视频里发生了什么？

I didn't want him to see what was going on.

我不想让他看到正在发生的事。

Only yesterday did I realize what was going on .

只是到了昨天。我才意识到情况是怎样的。

Jane heard a noise and wondered what was going on.

简听到一声巨响，不知道发生了什么事情。