If you want to keep healthy, you should have good habits. What is a habit? It is something we do very often. We don't even think when we do it. It has become a part of our lives. "Early to bed, early to rise makes a man healthy, wealthy and wise." This is an old English saying. Do you know what it means? It means that we must go to bed early at night and get up early in the morning. If we do, we shall be healthy, rich and clever. Is this true? Perhaps it is. We know the body must have enough sleep. Boys and girls need eight or nine hours' sleep every day. Some people go to bed late at night and get up late in the morning. This is a very bad habit. Then you will not think or do your work well. Of course, you can't be healthy, wealthy or wise. When we get up early in the morning, we can go out and do morning exercises. Exercise means doing things with the body. Walking, running jumping, swimming, and playing ball games are all exercise. If we don't exercise, our body will become weak. Exercise helps the blood   to move around inside our body. Blood takes food to all parts of our body. Our body also needs air to breathe. Without air, we will die. We must have lots of clean fresh air if we want to be healthy. That is why many people like to go out to do morning exercise. Which of the following habits is NOT GOOD?
Don't go to bed until twelve o'clock.. Take a walk after supper. Run in the open air early in the morning. Climb hills for half an hour early in the morning.