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 them lead a different kind of 1ife.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.To be successful,a person has to work like a dog.Such hard work can make people dog-tired,or 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 all old dog new tricks.They believe that older people do not like to learn new things and wilt not change the way they do things. 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.She may not treat him nicely until he apologizes.However,the husband may decide that it is best to 1eave things alone and not create more problems.He might decide to let sleeping dogs lie. Dog expressions are also 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 correct statement about the dog in the expression"to 1ead a dog's life"is    _    .
a lucky dog a homeless dog a clever dog a tamed dog