I am a teacher
I am not a teacher
I am hungry
I'm not hungry
I'm a cat
I'm not a cat
It is cold
It isn't cold
The cats are scared.
The cats aren't scared.
They are old
They aren't old
It is tired.
It isn't tired.
They are big
They aren't big
They are dogs
They aren't dogs
He is a man.
He isn't a man.
A panda is small.
A panda isn't small.
They are new books
They aren't new books