88. You'd better try to give up ___________ (smoke). It's too bad to your health.

87. We ___________ never ___________ (be) to Hawaii.

86. Miss Green ___________(be) in China for 6 years.

85. ___________you ever ___________(ride) a horse before?

84. We ___________ (not see) each other since he ___________ (leave) here.

83. Our teacher told us time ___________ (be) life.

82. These exercises must ___________ (do) by yourself.

81. It ___________ (snow) hard now. We'd better ___________ (not go) home right now.

80. Tennis ___________ (invent) a hundred years ago.

79. English ___________ (speak) in Canada.