Do you know why you sleep? You may think it's because you're tired. Or perhaps you've been told sleep is good for you. Yet no one knows exactly why or how people sleep.
    Until the early 1950s, most scientists thought the body and brain rested during sleep. Then a scientist watched people sleep. He noticed that during periods of between 5 and 30 minutes each, sleepers' eyes made rapid movements, as if they were watching something. He called these periods REM sleep, for Rapid Eye Movement. Periods when sleepers' eyes did not move he called non-REM sleep.
    Whenever the scientist woke people during REM sleep, they were having vivid dreams. Measurements showed that sleepers' pulses（脉搏）went up quickly during REM sleep. Their breathing, heartbeat, and the blood going to the brain also increased. Far from being a time of rest, REM sleep is a time when the body is hard at work. Scientists still don't know the reason for this. Some believe REM sleep makes learning easier. Babies spend a lot of time in REM sleep. Because of this, some scientists believe that REM sleep helps the brain grow. Others think REM sleep is a time for the brain to empty the day's garbage.
    One thing all the scientists agree on is that sleep is necessary. Without enough sleep, people make mistakes. Most major car accidents happen during the early morning hours, when people are sleepiest.

   As a child, I was really afraid of the dark and of getting lost. These fears were very real and caused me some uncomfortable moments.
Maybe it was the strange way things looked and sounded in my own room at night that scared me so much. There was never complete darkness, but always a streetlight or passing car lights, which made clothes on the back of a chair take on the shape of a wild animal. Out of the corner of my eye, I saw the curtains(窗帘) seem to move when there was no wind. A very low sound in the floor would seem a hundred times  louder than in the day. My imagination (想象) would run wild, and my heart would beat fast. I would lie very still so that the "enemy(敌人) " would not discover me.
   Another of my childhood fears was that I would get lost, especially on the way home from school. Every morning I got on the school bus right near my home. That was no problem. After school, though, when all the buses were lined up along the street, I was afraid that I would get in the wrong one and be taken to some other strange places. On school or family trips to a park or a museum, I wouldn't let the leaders out of my sight.
   Perhaps one of the worst fears of all I had as a child was that of not being liked or accepted by others. Being popular was so important to me then, and the fear of not being liked was a serious one.
   One of the processes(过程) growing up is being able to realize and overcome our fears. Understanding the things that scared us as children helps us achieve greater success later in life.

   As a child, I was really afraid of the dark and of getting lost. These fears were very real and caused me some uncomfortable moments.
Maybe it was the strange way things looked and sounded in my own room at night that scared me so much. There was never complete darkness, but always a streetlight or passing car lights, which made clothes on the back of a chair take on the shape of a wild animal. Out of the corner of my eye, I saw the curtains(窗帘) seem to move when there was no wind. A very low sound in the floor would seem a hundred times  louder than in the day. My imagination (想象) would run wild, and my heart would beat fast. I would lie very still so that the "enemy(敌人) " would not discover me.
   Another of my childhood fears was that I would get lost, especially on the way home from school. Every morning I got on the school bus right near my home. That was no problem. After school, though, when all the buses were lined up along the street, I was afraid that I would get in the wrong one and be taken to some other strange places. On school or family trips to a park or a museum, I wouldn't let the leaders out of my sight.
   Perhaps one of the worst fears of all I had as a child was that of not being liked or accepted by others. Being popular was so important to me then, and the fear of not being liked was a serious one.
   One of the processes(过程) growing up is being able to realize and overcome our fears. Understanding the things that scared us as children helps us achieve greater success later in life.

   Do you have the ability to live cheaply? Now here's a true story of an American girl，Sarah．1Sarah left university，she began to live in New York City on her own．She 2 a job in a publishing house，but the salary(薪水)was 3 $30，000 a year．Her parents thought her life would be hard，but Sarah 4live on her salary and still saved $5，000 in a year．How was that 5 in one of the most expensive cities in the world?
   Cheap living 6starts with keeping the big cost small．For most people，that 7housing．So Sarah chose to share a flat with three other friends．Her next biggest cost was  8．When she ate out，she went to cheap restaurants．9 she bought a $9．99 whole chicken at a local restaurant．She then10the chicken bones(骨头)home and made soup out of them．Nowadays young people often 11 a lot of money on entertainment(娱乐)．But Sarah said，"I enjoy walking 12 in New York City．I love going to museums and parks．" Did Sarah feel poor13 cheap living? Not really．She even managed to take two trips，one to the Netherlands，14to Portland．
   “Don't think of saving money as something15．It's a kind of game，"said Sarah． 

   Have you ever seen a movie called “ The Choir Boys”(《放牛班的春天》)？The French movie tells the story of a group of naughty boys who learn music from a dedicated(尽职的) teacher. In Shanghai, there is also a group of children learning music. But their story is a bit different.
   The musical group, “Shepherds'Kids” , was founded(建立) by the Shanghai Jiuqian Volunteer Center. There are about 40 students in this group. Their parents are migrants(打工者) working in Shanghai.“ The music courses are free,” said Zhang Yichao, founder of the group. “We just want to make the children's lives more colorful.”The kids learn singing, dancing and musical instruments. Their teachers are volunteers from high schools.Learning music is not an easy job, especially for these migrant workers' children.“I never know the musical stave(五线谱) before,” said Hua Delong, 13. “Sometimes it was really hard to study.”Tang Yue is a volunteer teacher at the center. She is a student from Shanghai Ping'he Bilingual High School.“These kids face difficulties bravely,” said Tang. “Sometimes they have to help their parents do housework and have little time to practice, but I never hear them complain.”
   Their hard work has paid off(回报). Today many people know the group. They have even performed as a choir for foreign pop stars.
Li Luo, 14, told “ Teens” how appreciative she was of the group.“I had little fun before. I seldom(很少) watched TV. Study seemed the most interesting thing in my life. “Shepherds' Kids has given me a new life.”