our earth, or else it will be no longer fit for us to live on.

Trees on the hills can stop the rains from        away the soil.

It never occurred to me________ you could succeed in persuading him to change his mind.

Newton was sitting under an apple tree ______ an apple fell onto his head.

I am going to do ______ I can ______ him a good impression.   

Children under sixteen are not permitted to participate in such kind of activities _____ bad for their mental development.

_____ to be a press conference at the town hall tonight. _____ to be broadcast live.

______and I’ll get the work finished.

—Why are you so late?
—I was in half the way when it______to me that I had left my notebook home，so I had to fetch it.

      but he still can not understand it.