阅读理解。 Are you in shape? To find out, ask yourself some questions: Do I exercise regularly? Do I ever walk places instead of driving my car? Do I ever play sports for fun? Do I ever take the stairs instead of the elevator? If you answered no to any or all of the above questions, you are probably out of shape and need to start a fitness program. Exercise is very important. It improves your strength and blood circulation (循环). It gives you more energy. It can help you relax and sleep well, and it can help control your weight. In fact, the U. S. Surgeon General says that exercise can help prevent heart disease, diabetes, obesity, and osteoporosis (a disease that weakens the bones). The first step is to make a program. A good fitness program should be fun. It should involve (包含) both your arms and your legs, and it should help you to build endurance(the ability to do exercise for a long time). To make a good program for yourself, first you should think about the types of activities you like to do, what you think you are able to do, and when you will have time to do it. A good exercise program will involve cardiovascular activities, such as running, biking, swimming, roller skating, playing soccer or tennis, or jumping rope. It will also involve weight-bearing exercise, such as weightlifting, and stretching activities. Also, daily, low-intensity activities such as walking, gardening, dancing, and climbing stairs are good for your physical health. So what are you waiting for? Cet off of the sofa and start exercising. Sign up for yoga, tai chi, or pilates. Join a gym or a running club, or just start walking a half an hour every day. Every little bit helps! 1. We can learn from the passage that _______. A. exercise can prevent all kinds of diseases B. a good exercise program should be exciting C. exercise can help you control your weight D. it' s not necessary to make an exercise program 2. A good exercise program should involve _______ types of activities. A. two B. three C. four D. five 3. Which of the following is low-intensity activities? A. swimming B.  jumping rope C. weightlifting D. climbing stairs 4. What does the writer mainly tell us? A. Exercise is important and should be part of your daily life. B. A good exercise program can help you a lot to keep healthy. C. Exercise can improve your strength and blood circulation. D. Start to make an exercise program when you are out of shape.