In China when caught, those corrupt(腐败的) officials are sometimes limited to _________ in a certain place, only __________ their problems within an appointed time(规定的时间).

The boy was curious about how the waste paper was into a model kite

He told me that by the end of this yearthey______together for twenty years．

Tom is a sunny man— Yeah______ he is poor, he looks happy[ ]

The experts have given some practical advice ______ the problems that most people are concerned about in food safety.