Most of us still wonder ___________ it is ________ makes those honest peasant workers, without being paid at all, resign themselves to the bosses.

----Are you sure it’s going to snow this weekend?    ----_____.

 —Isn’t it time you _______ down to _______ your own things? —I’m sorry for the delay, Dad.

Not only ________ give people relaxation and pleasure, but ________ increase their knowledge of any kind.

     private cars are bringing us convenience, they may also cause traffic accidents and pollution.