1. I can't make it at that time.

我脱不开身啊。

2. Sorry, I have plans.

对不起，我有事。

3. You see I'm in the middle of something.

你看，我正忙着呢。

4. I'm sorry, I'm otherwise engaged.

对不起，我有其他安排了。

5. I have other fish to fry.

我还有别的事要做。

6. I am in a meeting. I'll call you later.

在开会呢，过会儿打给你。

7. I am tied up.

我有事走不开。

8. I'd love to,but I am busy.

我想，但是我很忙。