Is he drinking water?
No, he isn't. He's drinking milk.
Is she singing? Yes, she is. / No, she isn't.
Yes, she is.
Are they having fun?
The girl is having fun but the cat isn't.
What are the fish doing?
They're flying.
What is he doing?
He's running.
Is it swimming?
Yes, it is.
Is she feeling happy? Yes, she is. / No, she isn't.
No, she isn't. She's feeling sad.
What are they doing?
They're dancing.
Is she laughing? Yes, she is. / No, she isn't.
No. She isn't.
What are they doing?
They're sleeping.
Is he eating salad?
No, he isn't. He's eating cookies (or biscuits).