~ではない (negative copula)

She isn't the cheerful woman she used to be.

I didn't mean it like that.

Those who don't know how to be silent are not skilled speakers.

She isn't the kind of insensitive girl who would laugh at a funeral.

'Software development' is not 'manufacturing.'

She's not much of a poet.

I don't think she's happy.

She's anything but honest.

She isn't a doctor — she's a teacher.

Isn't she a doctor?

She's not in the mood to do that work.

She's not my type.

The books in this room aren't mine.