People often say that dog is the man’s best friend. Over thousands of years,Man has taught his dog to do many kinds of work besides guarding the home.
For example Sheepdogs are famous for their ability to control a flock of hundreds of sheep. Dogs have been used to aid the disable people for centuries. A guide dog can lead its blind owner.
Nowadays ,The dog can be taught to turn on light switches, open refrigerator door and dial telephone for their disable owners. For majority of people, however dogs are simply pets or friends for both the young and old members of the family.
