40. If we are free, we ______ (help) you plant trees.

39. Can you ______ (play) football?

38. Just let me ______ (know) soon.

37. I have to ______ (ask) my parents first.

36. Would you like ______ (stay) at home today?

35. The birds ______ (sing) in the tree now.

34. ______ (not drop) litter on the ground.

33. What ______ she ______ (say) just now?

32. He is always very careful when he ______ (drive).