Here are the best options for the exercise:

33. D. doesn't know
34. A. If I hadn’t eaten too much, I wouldn’t feel so sick now.
35. B. would have made
36. A. is
37. B. had
38. D. wouldn't have to work on Sunday.
39. A. has sent
40. B. play
41. D. have had
42. A. had studied
43. C. go
44. D. mosque
45. A. population
46. A. adding
47. B. compulsory
48. A. beautiful
49. D. shrine
50. A. watches

Feel free to ask if you have any more questions!