It is ______ to spend money in preventing illnesses by promoting healthy living rather than spending it trying to make people ______ after they are ill.

I think students should have mobile phones to call their parents.–______. They often use them to play games instead.

Upon ______the classroom， I started thinking about my mother.

In no case _____go _____the law of nature or we’ll meet endless suffering[ ]

It was for his excellent work _____he had done lately ____ he was awarded the Nobel Prize for Physics.