阅读理解

    Many people have the wrong idea about pigs. Pigs are really very clean animals. On farms, they live in dirty places. So, they become very dirty. But in the wild, pigs keep very clean.

    They are also really smart. They may be smarter(更聪明) than dogs. So, pigs can learn things from people.

    Pigs are very friendly animals. Some people raise(饲养) them as pets. Of course, people raise the small kind, not the big kind. Small pigs are very cute. And they don't break things in the house. Big pigs usually live outside on farms, not in people's houses.