I'm sorry, but I can't find the book you lent me.

很抱歉！我找不到你借给我的那本书了。

I haven't the least idea.

我一点儿也不知道。

Thanks. I'll certainly do that.

谢谢了，我一定会的。

Would you mind if I opened the window?

我开窗，可以吗？

That radio's pretty loud. Could you turn it down, please?

收音机太响了，你能把声音开小一点吗？

So I've heard.

我听说是这样。