Conversation

How to offer/refuse

Would you like a Coke? - Yes, I'd love to.

Yes, please.

No, thank you.

Understanding

I didn't quite get that.

Can you repeat that, please?

I didn't understand you.

How to ask/argue

Are you saying that ...?

Can you explain that?

Sorry to interrupt you, ...

I actually wanted to say that ...

Well, ...

I don't think so.

I'm sure that ...

There's nothing more to say.

Obviously I don't need to say that ...

General

Besides ...

It doesn't matter.

Don't mention it.

I must apologize for being so late.