He is here. / Is he here?

I am crazy. / Am I crazy?

He can play guitar. / Can he play guitar?

You must go now. / Must you go now?

I should stop. / Should I stop?

They are French. / Are they French?

There is a car. / Is there a car?

There are errors. / Are there errors?

The film has started. / Has the film started?

John had eaten. / Had John eaten?