What's she doing?
She's running.
What's she doing?
She's throwing a ball.
What's she doing?
She's playing tennis.
What's she doing?
She's playing basketball.
What's he doing?
He's playing the guitar.
What's she doing?
She's playing the piano.
What's she doing?
She's skateboarding.
What's he/she doing?
He's/She's watching TV.
What's he doing?
He's riding a bike.
What's he doing?
He's catching a ball.
What's she doing?
She's swimming.
What's she doing?
She's hitting a ball./She's playing baseball.
What's he doing?
He's kicking a ball.
What's he doing?
He's playing football.