He -
He isn't surfing the Internet.
They -
They aren't having a picnic.
She ?
Is she doing homework?
You ?
Are you riding a bike?
He -
He isn't listening to music.
They +
They are playing with a pet / a dog.
I ?
Am I visiting family?
We +
We are cooking.
I -
I am not taking pictures.
You -
You are not hanging out (with friends).