A comma is a punctuation mark used to indicate division.
The comma mark is: ,
- Between question tags and yes-no responses
- She’s very nice, isn’t she?
- You don’t like her, do you?
- No, thank you.
- Between vocatives and discourse markers
- Tell me, John, what made you do this.
- Wow, that sounds great!
- Well, I don’t quite agree with you
- subordinate comment clauses put together with the main clause
- To be honest, he shouldn’t behave like this.
- If I may say so, you would be better off without him.
- Nevermind, I’ve already bought some myself.
External link to Comma exercises (1226).