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?