He (positive be)
He's British.
We (negative be)
We aren't/We're not Italian.
I (positive be)
I'm Spanish.
I (negative be)
I'm not Argentinian.
She (positive be)
She's Japanese.
They (positive be)
They're Greek.
You (negative be)
You're not/You aren't Brazilian.
He (negative be)
He's not/He isn't Chinese.
She (negative be)
She isn't/She's not German.
We (positive be)
We're Turkish.
He (positive be)
He's American.
We (positive be)
We're Mexican.
I (positive be)
I'm English.
They (negative be)
They're not/They aren't French.
You (positive be)
You're Russian.