李叔叔正在书店买书.

And Mr Li is buying some books in a bookshop.

这就是为我们修电脑的李叔叔。

This is Uncle Li who mended computers for us.

我也许得帮助李叔叔组装那台机器。

I may help Uncle Li fix the machine.

只有李叔叔知道这件事是怎么发生的。

Only Uncle Li knows how it happened.

李叔叔让那个男孩在那里呆了很长一段时间。

Uncle Li kept the boy there for a long time.