I.

41. I suggest you should start revising for the coming exam

42. His father is believed to have died in a car accident

43. I wish i could play the guital well

44. She said she was going to leave there for Hue the next day

45. No matter how difficult that exercise was, my brother could do it quickly

II.

46. Don't forget to check for spelling mistakes before you hand in your composition.

47. Unless you leave me alone, i will call the police 

48. If you happen to to be in London, come and see me

50. Were I to meet the author one day, I would ask him to sign my copy of his new book