1. The cat is climbing the tree.
The cat isn't climbing...
Is cat climbing...?
2. His mum is cooking now.
His mum isn't cooking now
Is his mum cooking now?
3. Mike's dad is watching TV now.
Mike's dad isn't watching TV now
Is Mike's dad watching TV now?
4. She's feeding her pet now.
She isn't feeding her pet now.
Is she feeding her pet now?
5. She's sleeping now.
She isn't sleeping now.
Is she sleeping now?
P.S. сначала идет утвердительная форма.
Потом отрицательная, далее вопросительная.