Tag questions (also called question tags) are used at the end of a sentence to confirm information or sometimes just to encourage a speaker to continue:
You haven’t renewed your passport yet, have you?
A: I used to live in Venice.
B: Venice is a lovely city, isn’t it?
Note that the tag question is the negative of the main verb clause:
You haven’t... have you?
It is...isn’t it?
Peter can...can’t he?
Jake left… didn’t he?
...and so on.