Sue is sending an email.
Is Sue sending an email?
Who is sending an email?
Sue is sending an email, isn't she?
Is Sue or John sending an email?
What is Sue sending?
What is she doing?
She's riding a scooter.
Is she riding a scooter?
Who is riding a scooter?
Is she riding a scooter or bicycle?
In what is she riding?
She is riding a scooter, isn't she?