Americans use many expressions with the word “dog”. People in the United States love their dogs and treat them well. They take their dogs for walks, let them play outside and give them good food and medical care. However, dogs without owners to care for lead a different kind of life. The expression “to lead a dog’s life” describes a person who has an unhappy existence.
Some people say we live in a dog-eat-dog world. That means many people are competing for the same things, like good jobs. 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 dog-tired. And, the situation would be even worse if they became sick as a dog.
Still, people say every dog has its day. 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.
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. Mean dogs are often used to guard this property. They bark or attack people who try to enter the property. However, sometimes a person who appears to be mean and threatening is really not so bad. We say his bark is worse than his bite.
Doghouse provide shelter but they can be cold and lonely in the winter. Husbands and wives use this doghouse term when they are angry at each other. For example, a woman might get angry at her husband for coming home late or forgetting their wedding anniversary. She might tell him that he is in the doghouse. However, the husband may decide that it is best to leave things alone and not create more problems. He might decide to let sleeping dogs lie.
Dog expressions also are used to describe the weather. The dog days of summer are the hottest days of the year. A rainstorm may cool the weather. But we do not want it to rain too hard. We do not want it to rain cats and dogs.
The passage tells us something about________.

A．dogs and their life	B．the expressions that describe dogs
C．the meaning of expressions with the word “dog”	D．the structures of dog expressions

By saying _______, we compare people to dogs in bad ways.

A．“meaner than a junkyard dog”	B．“to work like a dog”
C．“teach an old dog new tricks”	D．“as sick as a dog”

By saying ________, we mean every person enjoys a successful period in life.

A．“he lives in a dog-eat-dog world”	B．“he leads a dog’s life”
C．“he is in the doghouse”	D．“every dog has its day”

If we advise the others to leave things alone and not create more problems, we say_______.

A．“become sick as a dog”	B．“rain cats and dogs”
C．“let sleeping dogs lie”	D．“stay in the doghouse”

It has been really hot these days, as _______.

A．it rains cats and dogs	B．we are having the dog days of summer
C．we’re leading a dog’s life	D．we’re in the dog’s house