Every possible means _____ to prevent the air pollution, but the sky is still not clear. 

Tom together with her good friends ________in the playground.They ________playing basketball.

 One-third of the area ________ covered with trees. About seventy percent of the trees _______ been planted recently.

. My suggestion is that Tom ______________ there on time.

 An iron and steel works, with some satellite factories, ____ to be built here.