People are busy working every day, so they do not have enough time to do exercise. As a result, many people become too fat or too thin. To keep our bodies healthy, we have to do exercise every day. There are many kinds of exercises. Bending   and stretching   helps us move easily. Before we play ball games or swim, it is better for us to do bending and stretching exercises first. This kind of exercise is something called warm-up exercise. Running is also a good exercise.  If we cannot run fast, we can jog. Jogging means running slowly Again, before we run or jog, we must do warm-up exercise. Also, we should not run or jog in busy streets. The air there is often dirty. Some people like weight lifting because it can make their bodies strong. Also, we need to do warm-up exercise before weight lifting. Why do some people like weight lifting?
Because it can make them thin. Because it can make their bodies strong. Because it can make them work well. Because they don't like other exercises.