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