Dogs are our best friends. But it's hard to believe that they used to be wild animals.
Thousands of years ago, you couldn't find dogs. You could find wolves ( 狼 ) . Wolves and humans lived side by side. The wolves probably ate the food people threw away around their villages. As time went by, these wolves started to be guard dogs and help to drive away dangerous animals. Since then, we have been friends with dogs.
Dogs communicate through body language and sound. It might bark(吠) with excitement give you a lick( 舔 )or wag( 摆 动 )its tail to show its happiness. Wagging its tail back and forth(来回地) means a dog feels relaxed and friendly. Wagging its tail low tells you that a dog feels worried. Standing its tail straight up tells you that a dog feels nervous.
Dogs are lovely animals. Scientists have found that keeping a dog can make people healthier and people can have a higher level of physical activity. ____ If you want to keep a dog as a pet, make sure your family has enough space, money and the time that you need to care for a dog. Play and exercise are important for dogs to stay happy and fit. Some dogs like to jump with their owners or go for a swim. For most dogs, the most important job of all is bringing love and joy to their families.
