21. Please open the window, ____________?

20. He shouldn’t make trouble, _________?

19. I need write a letter, __________?

18. They must stay at home, _________?

17. Wendy can’t swim, ____________?

16. Peter didn’t go home, ____________?

15. Anne and Sue have come already, _____?

14. They have many friends, ___________?

13. She ate two bananas, _____________?

12. Ann and Tom will not study hard, ______?