我不知道用英语怎么表达用英语怎么表达？

I don't know what to make of the new manager.

这位新经理，我不知道怎么评价他才好。

I don't know what you're on about.

我不懂你在谈什么。

I don't know how you can say things like that.

真想不到你怎么会说出这种话来。

I don't know how she puts up with him.

我不明白她怎么受得了他。

I don't know if I can come but I'll try.

我不知道是否能来，但我尽可能来。