84. Parents should help their children to form good 　　　　(习惯).

83.　　　

83. We gave our classroom a 　　　(彻底)cleaning before the National Day.

82.　　　

82. The artist held an 　　　(展览) of his works last month.

81.　　　

81. We've got to be 　　　　(实际) and buy only what we need.

80. The patient kept 　　　(咳嗽) all night.　　　　 80.　　　

79.　　　

79. I changed into my sports shoes so that I could walk more 　　　(舒服).