I’m sorry to have kept you waiting.

不好意思让您久等了。

That’s OK.

没关系。

Mr. John is tied up (忙)at the moment.

John先生现在很忙。

When shall I try him again?

我什么时候可以再打过来?

Could you call back in 30 minutes?

你可以过30分钟后再打过来吗?

Yes, I well.

好的。