25. D→entertainment

      B→sings

26. D→listened

      D→had died

27. C→because of

      C→because

28. B→happily

      B→mountainous

29. Unless the man arrives, we will start the conference without him

Unless you come soon, you may not meet us

30. It is very important to speak English in class

It is not easy to help him overcome the sock

31. I suggest going to the supermarket

Mrs. Hoa suggested I should turn off the lights before going out

32. My sister, who always does her homework before going out, is a hard-working student

The girl who lives next door to us, is very friendly

33. I've drunk 6 cups of coffee today since I've got a headache

Although it rained hard last night, he came to the meeting on time

34. If we pollute the water, we will have no fresh water to use

If I see Mary today, I will call you