Are they catching a ball?
Yes, they are.
Is he riding a bike?
Yes, he is.
Are they swimming?
Yes, they are.
What are they doing?
They are singing.
What is he doing?
He is singing.
Is she kicking a ball?
Yes, she is.
Is she dancing?
Yes, she is
What is she doing?
She is skipping.
Is she dancing?
No, she isn't
Is he hitting a ball?
Yes, she is.
Is he throwing a ball?
No, he isn't.
What is he doing?
He is skating.