There are many ways to help improve your health like eating healthy food. Taking exercise and getting medical help. But the easiest and cheapest way to improve your health is just to sleep eight hours or more every night. The general sleeping rule is that the younger you are， the longer sleep you need. But regardless of （不管） age， some people need to sleep more while for some a few hours is enough.
　　The problem with sleep is that more and more people in the world are not sleeping enough. According to the World Health Organization over half the people in the world may be sleep-deprived. Having less sleep not only makes people feel tired but also causes accidents. In the United States alone， sleepy drivers cause at least 100，000 traffic accidents a year. Also sleep problems can cause medical problems such as high blood pressure （血壓）.
　　Why are so many people sleep-deprived？ Part of the reasons may be cultural. In the American culture， people put a higher value on work than on sleep. In fact， people who sleep a lot are usually seen as “lazy”. Also， you can sometimes hear some people say proudly that they dont have much time to sleep. They only sleep four or five hours a night. It seems that the less you sleep， the more work youll do.
　　How do we teach these people to learn the value of sleep？ Perhaps they may listen to the advice of Dr. James Maas an expert （专家） in sleep. He says， “Sleep is like a credit （信用卡） card. When you sleep less， you are only borrowing time. You always have to pay it back. The more hours you dont sleep， the more hours you shouldt sleep to ‘pay back’ the hours on your ‘sleep credit card’.”
　　For those who value work more than sleep， they should listen to what a famous person once said， “Dont think you will be doing less work because you sleep during the night. That is a foolish idea which is held by people who have no imagination. You will be able to do more.”
　　根据短文内容，选择最佳答案。
　　1. According to the writer， the easiest and cheapest way to improve health is to ________.
　　 A. eat healthy food every day                             B. take exercise as much as possible
　　 C. get medical help whenever necessary        D. sleep eight hours or more every night
　　2. What does “sleep-deprived” mean in Paragraph 2？ 　　 A. Having a good sleep.                                        B. Excited about sleep.
　　 C. Having less sleep.                                             D. Interested in sleep.
　　3. According to Dr. James Maas， what is sleep like？
　　 A. An hour.          B. A report.                 C. A credit card.            D. A piece of paper.
　　4. What do the words of the famous person mean in Paragragh 5？
　　 A. Sleeping during the night is foolish.          B. Sleeping during the night is helpful.
　　 C. People have no courage.                     D. People always do less work.