pronoun+be not
pronoun be+not
100

I am not hungry.

I'm not hungry.

100

That dog is not friendly.

That dog isn't friendly.

200

She is not my sister.

She's not my sister.

200

She is not my sister.

She isn't my sister.

300

He is not my brother.

He's not my brother.

300

He is not my brother.

He isn't my brother.

400

They are not friends.

They're not friends.

400

They are not friends.

They aren't friends.

500

We are not late.

We're aren't late.

500

We are not late.

We're not late.