2. The crowd were cheering when Nam was winning the race

4. Before he traveled England, he had studied English for two years

5. We are happy to get good marks

7. The teacher let the students open their books when they did the test

12. His father stopped smoking cigarette two years ago

16. After they had had dinner, they watched TV

17. Last night, I saw a thief stealing the neighbour’s bike

18. These clothes need washing They are very dirty

19. I were doing  my homework while my brother and sister were watching TV

21. Would you mind opening the door? - it is very hot

22. I suggest taking a shower instead of a bath to save water

25. The soccer match had already/began when we arrived the stadium

26. It is no use reading that novel. It is boring.

33. You had better learn harder on your exam

35. It took him an hour doing these exercises yesterday

36. I suggest going to school or to work by bikes to save energy

37. Before they married, they had built a house