Ответ:

12. Why have you done your homework already?

13. How has she made this fantastic cake?

14. Why have I missed the plane?

15. They haven't gone to bed.

16. It has rained a lot this week.

17. Have they used a credit card before?

18. Have we had enough to eat?

19. She hasn't played basketball before.

20. I have worn a kimono.