question tags

[joham]

She might have left, hasn't she/ didn't she?
She might have left the day before yesterday, didn't she?
She can't have been in the cinema then, was she?

Would 'mightn't she?' and 'can she' be better than the original tags? How would native speakers use question tags in sentences like these?

Thank you in advance.

[5jj]

She might have left, mightn't she?
She might have left the day before yesterday, mightn't she?
She can't have been in the cinema then, can she?

These are the only possible tags.

[JohnParis]

Hello Joham

5jj's answers to your questions are all solidly correct.

I would just like to point out that the tag "mightn't" is not something you hear in conversation very often. It's quite old-fashioned and apart from films, television and the theater, I haven't heard it spoken in regular conversation or seen it written in many decades. I think most speakers would choose to say something like, "right" at the end of your example sentences.
She might have left, right?
She might have left the day before yesterday, right?

John

[Tdol]

How about might she not as the tag?

[5jj]

How about might she not as the tag?

Sorry. When I said the tags I gave were the only possible ones, I was thinking of the only possible verbs that could be used. I ignored the uncontracted forms. These are not commonly used, but they are perfectly correct. Indeed, in formal speaking and writing, they are more appropriate.