Why is she watching films?
Why are you wearing a costume?
Why is he writing an email to his friends?
Why is she listening to music in the kitchen?
Why are you taking your goggles ?
Why is he studying a lot?
Because she loves listening to music when she cooks.
Because he has a test.
Because I am going to the swimming pool.
Because he's inviting them to his party?
Because she likes watching films.
Because I am going to a costume party.