74 a couldnt 75 a can 76 b told 77 c is being built 78 a can't 79 c was given 80 c has been built 81 c neednt 82 a neednt 83 c would 84 a mustnt 85 a neednt 86 c were killed 87 c neednt 88 a was locked 89 b could 90 c have been told 91 c must 92 b can
84 a и b могут подойти +
87 а и с подойдут, но будет разное значение