The old scientist took up walking as a regular form of exercise, which, of course, is of great        to his heath.

In my opinion, it is the coach rather than the players that____.

 It's going to rain.Xiao Feng，will you please help me ________ the clothes on the line?

 ---I will have to think about it again．--- If you _    , you may lose the opportunity to compete altogether．

Three college students were accused _____ causing the accident on purpose and sentenced to three years in prison.