=>
29. natural
30. imagine
31. education
32. fluently
33. It is thought that he worked very hard last year.
34. I don't know what to review first for the coming test.
35. The book which I bought yesterday is very interesting.
36. Although they worked all night, they couldn't finish their reports in time.
37. The cost of living is very high in the city because most goods are very expensive.
38. My mom used to keep a diary when she was a high school student.
39. If you want to keep fit, you should eat a lot of fruits and do more exercise.
40. I dream of becoming a doctor in the future , so I decide to study medicine.