Did Susan have breakfast?

Who had breakfast?

What did Susan have?

Susan had breakfast, didn't she?

Did Dan write a postcard to his friend?

Who did Dan write a postcard to?

What did Dan write to his friend?

Who wrote a postcard to his friend?

Dan wrote a postcard, didn't he?

Did Alice buy some souvenir?

What did Alice buy?

Who bought some souvenir?

Alice bought some souvenir, didn't she?

How much souvenir did Alice buy?