Nowadays many people like to have dogs as their pets. Dogs are friends of man not only because they are lovely but also because they are faithful to their masters.
Dogs can do a lot of work for man. They play with us. They hunt with us. They keep door for us. But long ago, dogs all over the world were wild.
Dogs can date back to the Stone Age. All dogs have the same ancestor. It is believed that their ancestor was much like a wolf. Other animals, such as the fox, came from this ancestor, too. Hundreds of thousands of years ago, man began to tame wild dogs. After the dogs were tamed, they were trained. The strong dogs became working animals. They were trained to pull heavy loads. They learned to keep an eye on the sheep and other animals. Working dogs had other jobs, too.
Some dogs were not strong. But they could help man hunt for game. Other dogs were best as pets.
Today, there are more than 100 kinds of dogs in the world.
现在许多人都把狗作为他们的宠物。狗是人类的朋友，不仅因为它们可爱，而且因为它们对主人忠诚。
狗能为人类做很多工作。他们和我们一起玩。他们追捕我们。他们把我们的门。但很久以前，世界上的狗都是野生的。
狗可以追溯到石器时代。所有的狗有相同的祖先。据说他们的祖先很像狼。其他动物，如狐狸，来自祖先，太。几十万年前，人类就开始驯服野狗。狗被驯服后，他们被训练。强壮的狗成为人类工作的。人们训练它们拉重的货物。他们学会了照看羊和其他动物。工作犬有其他的工作，也。
有些狗不够强壮。但它们能帮人们寻找游戏。其他的狗是最好的宠物。
今天，世界上有超过100种的狗。