77.C. There is/was no knowing/telling...意为“没法知道或说等”.

76.B. have no business to do/doing sth. 意为“无权做某事”.

75.B.suggest意为“暗示”,从句时态根据需要而定.

74.B.

73.A.选动词原形构成祈使句.

72.B.make up one’s mind意为“决定”,后可接不定式或that从句作宾语.

71.C.问句为强调句型,强调句子(To get rid of the bad smell is difficult.)的主语.

70.D.appreciate后常接-ing形式作宾语,由题意可知应用其完成时态的被动语态.

69.C.过去分词短语作状语.

68.B.解析见56.