Many people like to keep dogs as their pets.But do you know dogs were wild(野生的)animals long,long ago?
The 1 ndline wild dogs were trained by 2 ndline in Europe about 10,000 years ago.These first“dogs”were not like 3 ndline we have now.They may have been small wolves.These dogs often came near humans to 4 ndline some food.Some of the young dogs were adopted(收养)by people and grew up with them.
Humans believed the 5 ndline were a help to them in many ways.The dog helped them to hunt(狩猎).They could smell and hear danger 6 ndline people could.They helped keep people 7 ndline on cold nights.So it was 8 ndline to raise the dogs.
Now,there are many different kinds of dogs 9 ndline they may look quite different from each other.Dog trainers think there are more than 400 different kinds in the world.The number keeps increasing with new kinds.
Since those early days,humans and dogs have always been together.We should 10 ndline them from now on because they are really our friends.