的展览做宣传。故选C项。

　　B

　　Physical education, or gym class, isn't required for all high school students. In some schools, it isn't offered for some different reasons. But should high school students have physical education? The answer is certainly "yes"．

　　 Today many people don't do sports.But as is known to all, doing sports is very important for an adult. Teaching teens the importance of a healthy lifestyle and making fitness plans now can help teens put exercise in the first place as an adult.

　　 High school isn't that easy. Many students are under a lot of stress. Stress can be harmful to a student's studies and life. Doing sports can help them deal with stress better, helping them live a happier life at school.

　　 The American Heart Association says that 10 million kids and teens suffer from obesity (肥胖症). Teens should get 60 minutes of physical activity per day to control their weight and to help their bones get stronger. The increase in activities that don't get teens to move around, such as video games and computer activities, means many teens don't get their required exercise. Physical education classes act as a public health measure to encourage activity and help teens have healthy weights.

　　 Inactivity increases teens' risk of developing many diseases. An active lifestyle offers a good way of protection from these health problems. As much as 75 percent of health­care spending goes toward treating medical conditions that can be hindered by lifestyle changes, according to the American College of Sports Medicine.

According to the President's Council on Fitness, Sports and Nutrition (PCFSN), students who performed five hours of physical activity each week improved their academic (学业的) performance. Students from programs with no physical activity