this is about question tag

8. If the main sentence is positive, the question tag should be
negative. The pattern followed by a negative question tag is:
auxiliary + n’t + subject
Examples of Negative question tag:
•You are free, aren’t you?
•George broke the glass, didn’t he?
•Your sister cooks well, doesn’t she?
•She can swim well, can’t she?

9. If the main sentence is negative, the question tag should be
positive. The pattern followed by a positive question tag is:
auxiliary + subject
Examples of Positive question tag:
•You aren’t busy, are you?
•He can’t drive, can he?
•Mohit doesn’t work hard, does he?
•They haven’t come yet, have they?

10. If there is an auxiliary verb (be, have, do, is, etc.) in
the main sentence, the question tag also contains
the same auxiliary verb.
E.g. It’s raining, isn’t it?
Similarly, if there is a modal verb (could, can, should,
etc.) in the main sentence, the question tag is also
constructed with the same modal verb.
E.g. They couldn’t hear him, could they?

11. In case, the main part of the sentence
doesn’t contain an auxiliary verb, the
question tag is constructed with the
relevant form of ‘do’.
E.g. He eats fish, doesn’t he?

12. There are certain peculiarities in the usage of
question tags that doesn’t follow the above
mentioned rules.
Examples:
•I am right, aren’t I?
•Let’s go to the beach, shall we?
•Wait a minute, can you?
•Have some more rice, will you?
•Somebody has called, haven’t they?
•There is a mosque in that street, isn’t there?

13. Additionally, the intonation of
question tags in spoken
English varies. In case of a real
question, you speak with a
rising intonation while if you
already know the answer, you
speak with a falling intonation.