59. Immediately after his arrival, things went wrong.
→No sooner 

58. You might fall if you are not careful.
→Be 

57. We should ban the use of pesticides, but we should also restrict
the use of other chemicals.
→In addition to

56. We must do something about the problem even if it costs a lot.
→Costly 

55. May I borrow your pen?
→Would

54. Why isn’t this TV working?

what.....

53. Local residents said they were against the new traffic scheme.
(DISAPPROVAL)

52. I don’t personally care if they come or not. (MATTER)

51. If interest rates are cut, the economic situation may improve.
(REDUCTION)

50. The teachers agreed to introduce the new methods.
(AGREEMENT)