阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Exercise is something【小题1】can help to make you look good, feel good and be 【小题2】（health）. Experts suggest that teenagers spend at least 30 minutes【小题3】(exercise)   five times【小题4】week. That is easy to do! Walking and travelling【小题5】bike count, and so do school sports. Often, teenagers give up sport, saying they have no time【小题6】(leave) after their studies. Many teenagers are【小题7】(surprise) to learn that when you exercise, your body【小题8】(produce) some chemicals that make you feel peaceful and relaxing and increase your ability【小题9】(concentrate) when you study. These chemicals even help you sleep【小题10】(well) at night.