以 Should we help the old who fall down on the st

When you take a walk a in any of the cities in the west,you often see a lot of people walking with dogs.It is still true that the dog is the most useful and faithful animal in the world.Butthe reason why people keep a dog have changed.In the old days,people used to train dogs to protect themselves against the attacks by other beasts.And later they came to realize that thedog was not only useful for protection but willing to obey their master.For example,when people used dogs for hunting,the dogs would not eat without permission what they caught.But now people in the city need not protect themselves against attacks of animals.Why do they keep dogs then?Some people keep dogs to protect themselves from robbery,but the most important reason is for companionship.For a child,a dog is his best friend when he has no friends to play with; for a young couple,a dog is their child when they have no children; for old couples,a dog is also their child when their real children have grown up.So the main reason why people keep dogs has changed from protection to friendship.