21. sells

22. will you repay

23. rises

24. works

25. will turn

26. burns

27. don't like

28. will have

29. see

30. will you promise

31. don't believe

32. likes

33. will make

34. won't be able

35. knows

36. ring

21 Unless he sells more he won't get much commission.           

22 If I lend you Ј10 when you will you repay me?

23 We'll have to move upstairs if the river rises any higher.

24 If he works hard today can he have a holiday tomorrow?

25 Ice will turn to water if you heat it.

26 If the house burns down we can claim compensation.

27 If you don't like this one I'll bring you another

28 Unless you are more careful you will have an accident.

29 Tell him to ring me up if you see him.

30 If I tell you a secret, you  will you promise not to tell it to anyone else?

31 If you don't believe what I say, ask your mother.

32 If he likes the house will he buy it?

33 If you will kindly sit down I will make enquiries for you.

34 Unless I have a quiet room I won't be able to do any work.

35 She won't open the door unless she knows who it is.

36 Should you require anything else please ring the bell for the attendant.