Good health is the person's most valuble possession.today, it is much easier to be healthy than it was the past. Modern people know more than health,have better food,and live in clean surroundings .Also ,scientists and doctors had learned how to deal with many diseases.Most people can quickly get for help from a doctor or go to a hospital since they are ill .As a result ,people in the modern world generally live longer than people is used to .People in developed countries can expect to live for twice as long as people who lived a little hundred years ago.