- Is she not a girl?
Isn't she a girl?
Am I not here?
- Am not I here?
Are tey all correct or right structured?
Isn't she a girl?
Am I not here?
Are tey all correct or right structured?
Regarding 4, it's worth noting that "am not" contracts, just like "is not" contracts to "isn't", but it (rather illogically) contracts to "aren't", just like "are not". A few dialects have the separate contraction "amn't", but it's not widespread across dialects. So 4 should be "aren't I here?.
With that aside, all of them are valid and grammatical. I'm not sure how often anyone would have cause to use "aren't I here", though.
The contracted versions of expressions like these can be the most natural of options. Sometime they aren't. There's a difference in emphasis and nuance between the options as well, though the details depend on dialect.
Is she not a girl?
This can be an archaic-seeming way of reminding people that someone is a girl, much like "if you prick me, do I not bleed?". It might be used to assert that she had some fundamental or stereotypical characteristic of girlhood.
Isn't she a girl?
This would be used to express surprise that she wasn't a girl, or to indicate that you had the impression that she was a girl, or to express surprise that a girl has been named. Like a sexist person hearing that someone achieved something and, feeling that a girl couldn't have achieved it, saying incredulously, "isn't she a girl?"
Am I not here?
Well, this one makes perfect sense, but is harder to find an explanation for. The most likely sounds like someone reminding people that they are present, for instance if they were being talked about as if they weren't there.