are doing是什么时态

We are doing our best with the limited resources available.

我们利用可获得的有限资源，尽最大的努力。

Go and see what the kids are doing, will you?

你去看看孩子们在干什么好不好？

Both mother and baby are doing well.

母子平安。

Mother and baby are doing well.

母子平安。

What the hell do you think you are doing?

你到底知不知道自己在干什么？