Unit 4 Wildlife Protection Using language课时作业

一.七选五

　　Americans use many expressions with the word "dog". People in the United States love their dogs and treat them well. __1__. However, dogs without owners to care for them lead a different kind of life. The expression, to lead a dog's life, describes a person who has an unhappy life.

　　Some people say we live in a dog­eat­dog world. __2__. They say that to be successful, a person has to work like a dog. This means they have to work very, very hard. Such hard work can make people dog­tired. And, the situation would be even worse if they became sick as a dog.

　　__3__. This means that every person enjoys a successful period during his or her life. To be successful, people often have to learn new skills. Yet, some people say that you can never teach an old dog new tricks. They believe that older people do not like to learn new things and will not change the way they do things.

__4__. People who are unkind or uncaring can be described as meaner than a junkyard dog. Junkyard dogs live in places where people throw away things they do not want. But mean dogs are often used to guard this property(财产). They bark or attack people who try to enter the property. However, sometimes a person who appears to be mean and threatening (威胁) is really not so bad. We say his bark is worse than his