do的过去式和过去分词是什么？

I could do it now, if you like.

如果你愿意的话，我现在就可以做这事。

A change of job would do you the world of good.

换一下工作会对你大有好处。

One major problem did present itself, though.

不过，确实出现了一个重大问题。

Someone might find out, and that would never do.

也许有人会发现，那是绝对不行的。

What do you charge for this type of work?

这种活你收多少钱？

What do you charge for work of this type?

这种活你收多少钱？