What's he doing?
He's playing on the bouncy castle.
What's the duck doing?
It is skateboarding.
What's she doing?
She is long jumping. (She is doing the long jump.)
What are they doing?
They are flying.
What's it doing?
It is jumping/hopping.
What's it doing?
It is driving.
What's it doing?
It's playing badminton.
What are they doing?
They are riding a bike.
What's it doing?
It is eating.
What's it doing?
It's playing on the water slide.
What are they doing?
They are riding the roller coaster.
What's he doing?
He's playing the violin.
What's it doing?
It is rollerblading.
What's it doing?
It is playing soccer.
What's it doing?
It is dancing.
What's it doing?
It is ice skating.