Americans use many expressions (习语) with the word “dog”. Many 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 them lead a different kind of life. The expression, to lead a dog's life, describes (描述) a person who has an unhappy life.
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.
Very often, 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 also use dog expressions 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.
What does “every dog has its day” mean?

A．A person has to work very hard.

B．A person won’t change his way.

C．A person doesn’t like to learn new things.

D．Every person enjoys a successful period.

Which of the following is WRONG according to the passage?

A．American people like keeping dogs a lot.

B．If a dog has no owner, its life will be hard.

C．People can use the word “dog” in many ways.

D．People can use the word “dog” to describe the house.

What’s the passage about?

A．Dogs’ lives	B．How to walk dogs
C．Expressions about dogs	D．Why people have dogs