When we can see well, we do not think about our eyes very often. It is only when we cannot see perfectly that we come to see how important our eyes are.

    People who are nearsighted can only see things that are very close to their eyes. Many people who do a lot of close work, such as writing, reading and sewing（缝纫）, become nearsighted. Then they have to wear glasses in order to see distant things clearly.

    People who are farsighted（远视的）suffer from just the opposite problem. They can see things that are far away, but they have difficulty reading a book unless they hold it at arm's length. If they want to do much reading, they must get glasses too.

    Other people do not see clearly because their eyes are not exactly the right shape. This, too, can be corrected by glasses. Some people's eyes become cloudy because of cataracts（白内障）. Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.

    When night falls, colors become fainter to the eye and finally disappear. After your eyes have grown used to the dark, you can see better if you use the sides of your eyes rather than the centers. Sometimes, after dark, you see a small thing to one side of you, which seems to disappear if you turn you head in its direction. This is because when you turn your head, you are looking at the thing too directly. Men on guard duty sometimes think they see something moving to one side of them. When they turn to look straight at it, they cannot see it any more, and they believe they were mistaken. However, this mistake happens because the center of the eye, which is very sensitive(敏感的) in daylight, is not as sensitive as the sides of the eyes after dark.

    As kids, my friends and I spent a lot of time out in the woods,"The woods" was our part-time address, destination,purpose,and excuse.If I went to a friend's house and found him not at home,his mother might say, "Oh,he's out in the woods,"with a tone of airy acceptance.It's similar to the tone people sometimes use nowadays to tell me that someone I'm looking for is on the golf course or at the gym,or even "away from his desk."For us ten-year-olds,"being out in the woods" was just an excuse to do whatever we feel like for a while.

    We sometimes told ourselves that what we were doing in the woods was exploring.Exploring was a more popular idea back then than it is today.History seemed to be mostly about explorers.Our explorations,though,seemed to have less system than the historic kind: something usually came up along the way.Say we stayed in the woods, throwing rocks,shooting frogs,picking blackberries,digging in what we were briefly persuaded was an Italian burial mound.

    Often we got "lost" and had to climb a tree to find out where we were.If you read a story in which someone does that successfully,be skeptical: the topmost branches are usually too skinny to hold weight,and we could never climb high enough to see anything except other trees.There were four or five trees that we visited regularly—tall beeches,easy to climb and comfortable to sit in.

    It was in a tree,too,that our days of fooling around in the woods came to an end.By then some of us had reached seventh grade and had begun the rough ride of adolescence.In March,the month when we usually took to the woods again after winter,two friends and I set out to go exploring.We climbed a tree,and all of a sudden it occurred to all three of us at the same time that we really were rather big to be up in a tree.Soon there would be the spring dances on Friday evenings in the high school cafeteria.

    Good writing starts with good ideas.If you write about things that you care about,you will write better.If you write about things that you don't care about,you'll be bored and your paper will not have many good ideas.

    Once you have a good idea,the next step is organization（组织）.Think through your paper before you start.Write an outline.You need to know what your main points are before you start your first paragraph.Use 2-4 main points, one paragraph each.

    In your central paragraphs,be concise and specific（简洁具体）.Give examples with details,not just general ideas. If you can say the same thing with fewer words,do it!Don't use big words.

    When you finish writing,look at your outline again.Did you really follow it or did it change as you wrote?Many times you find different ideas as you write.Look at your central paragraphs.What are their main ideas now?Are theses ideas in the introduction?I often write the introduction again to fit the paper after I finish writing.

    Every week in China, millions of people will sit in front of their TVs watching teenagers compete for the title Character Hero, which is a Chinese­style spelling bee (拼写大赛). In this challenge, young competitors must write Chinese characters by hand. To prepare for the competition, the competitors usually spend months studying dictionaries.

    Perhaps the show's popularity should not be a surprise. Along with gunpowder and paper, many Chinese people consider the creation of Chinese calligraphy (书法) to be one of their primary contributions. Unfortunately, all over the country, Chinese people are forgetting how to write their own language without computerized help. Software on smart phones and computers allows users to type in the basic sound of the word using the Latin alphabet(字母). The correct character is chosen from a list. The result? It's possible to recognize characters without remembering how to write them.

    But there's still hope for the paint brush. China's Education Ministry wants children to spend more time learning how to write.

    In one Beijing primary school we visited, students practice calligraphy every day inside a specially decorated classroom with traditional Chinese paintings hanging on the walls. Soft music plays as a group of six­year­olds dip brush pens into black ink. They look up at the blackboard often to study their teacher's examples before carefully trying to reproduce those characters on thin rice paper. "If adults can survive without using handwriting, why bother to teach it now?" we ask the calligraphy teacher, Shen Bin. "The ability to write characters is part of Chinese tradition and culture," she reasons. "Students must learn now so they don't forget when they grow up." says the teacher.

    For some people, music is no fun at all. About four percent of the population is what scientists call "amusic." People who are amusic are born without the ability to appreciate music or recognize musical notes (音调). Amusic people often cannot tell the difference between two-songs. Amusics can only hear the difference between two notes if they are far apart on the musical scale.

    As a result, songs sound like noise to an amusic. Many amusics compare the sound of music to pieces of metal hitting each other. Life can be hard for amusics. Their ability to enjoy music sets them apart from others. It can be difficult for other people to identify with their condition. In fact, most people cannot begin to understand what it feels like to be amusic. Just going to a restaurant or a shopping mall can be uncomfortable or even painful. That is why many amusics intentionally stay away from places where there is music. However, this can result in withdrawal and social isolation. "I used to hate parties," says Margaret, a seventy-year-old woman who only recently discovered that she was amusic. By studying people like Margaret, scientists are finally learning how to identify this unusual condition.

    Scientists say that the brains of amusics are different from the brains of people who can appreciate music. The difference is complicated, and it doesn't involve defective hearing. Amusics can understand other nonmusical sounds well. They also have no problems understanding ordinary speech. Scientists compare amusics to people who just can't sec certain colors.

    Many amusics are happy when their condition is finally diagnosed (诊断). For years, Margaret felt embarrassed about her problem with music. Now she knows that she is not alone. There is a name for her condition. That makes it easier for her to explain. "When people invite me to a concert, I just say, 'No thanks. I'm amusic,'" says Margaret. "I just wish I had learned to say that when I was seventeen and not seventy."

    Next autumn when you see wild geese heading south for the winter flying in a V formation you might think about what scientists have discovered as to why they fly that way.

    As each bird flaps(拍打) its wings, it creates an uplift(升力) for the bird immediately following. By flying in V formation the whole group adds at least 71% greater flying range(航程) than if each bird flies on its own.

    People who share a common direction and sense of community can get where they are going more quickly and easily because they are traveling on the push of one another. When a wild goose falls out of the formation, it suddenly feels the drag and resistance(阻力) of trying to go alone and quickly tries to get back into the formation to take advantage of the lifting power of the bird in front. When the head goose gets tired, it flies back into the formation and another goose flies to the front. It is wise to take turns doing difficult jobs whether it be people or wild geese flying south.

    Wild geese honk(发出雁叫声) from behind to inspire those up front to keep up their speed. When a wild goose gets sick or wounded by gunshots, and falls out of the formation, two other geese will fall out with that goose and follow it down to lend help and protection. They will stay with the fallen goose until it is able to fly or until it dies, and only then will they go on with their own or with another formation to catch up with their group.