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.

According to a review of evidence in a medical journal, runners live three years     1    (long) than non-runners. You don't have to run fast or for long    2    (see)the benefit. You may drink, smoke, be overweight and still reduce your risk of     3     (die) early by running. While running regularly can't make you live forever, the review says it     4     (be) more effective at lengthening life    5     walking, cycling or swimming. Two of the authors of the review also made a study published in 2014    6    showed a mere five to 10 minutes A day of running reduced the risk of heart disease and early deaths from all     7    (cause).

The best exercise is one that you enjoy and will do. But otherwise…   it's probably running. To avoid knee pain, you can run on soft surfaces, do exercises to    8    (strength)your leg muscles(肌肉),avoid hills and get good running shoes. Running is cheap, easy and it's always    9    (energy).If you are time poor, you need run for only half the time to get the same benefits as other sports, so perhaps we should all give    10    a try.