1 They are tall.
They aren't tall.
2. I am Helen.
I'm not Helen.
3. They are friends.
They aren't friends.
4. You are sleepy.
You aren't sleepy.
5. His cat is white.
His cat isn't white.
6. She is at home.
She isn't at home.
7.He is my brother.
He isn't my brother.
8. It is your seat.
It isn't your seat.
9. Martina and Jess are my students.
Martina and Jess aren't my students.
10. Elephants are huge.
Elephants aren't huge.