31. ……….(Pure/ Polluted/ Dust/ Pleasant) air is one of the many problems we have to solve.

32. I’ll be in trouble if I ………(lose/ will lose/ lost/ would lose) my passport.

33. We can eat at home or, ………..(when/ whether/ if/ which) you prefer, we can go to a restaurant.

34. If it is raining this evening, I …………(will go out/ don’t go out/ go out/ won’t go out).

35. Minh’s English is excellent. He speaks ………….(perfectly English/ English perfectly/ perfect English/ English perfect)

36. I’m disappointed …….(that/ when/ if/ how) people have spoiled this area.

37. He ………(hardly tried/ tried hardly/ hard tried/ tried hard) to find a job but he had no luck.

38. We couldn’t go on a picnic as planned ……..(however/ but/ because/ so) it was raining hard.