some rules of inserting question tag

A question tag is a small question(a question fragment) added to a statement to make it a question. The question usually has a 'yes/no' answer; it keeps the coversation flowing.

-If the statement is positive, the question tag is negative. If the statement is negative, the question tag is positive. For example:

She's a teacher, isn't she?

You haven't seen him, have you?

- The verb in the question tag is the same as that in the main part of the sentence. If it is an auxiliary verb, the same is used in the question tag. For example:

The students weren't here, were they?

- If there is no auxiliary in the main part of the verb, then the appropriate form of 'do' is used. For example:

Lions eat meat, don't they?

- Remember that 'I am' changes to 'aren't I' in the question tag.