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.