Поставь предложение в отрицательную форму. they are red. he is eleven. she is twelve. we are twenty. you are sad. it is big.

They aren't red. He isn't eleven. She isn't twelve. We aren't twenty. You aren't sad. It isn't big.

They are not red, he is not eleven, she is not twelve, we are not twenty, you are not sad, it is not big