If humans were truly at home under the light of the moon and stars, we would go in darkness happily, the midnight world as visible to us as it is to the vast number of nocturnal(夜间活动的) species on this planet. Instead, we are diurnal creatures, with eyes adapted to living in the sun's light. This is a basic evolutionary fact, even though most of us don't think of ourselves as diurnal beings. Yet it's the only way to explain what we've done to the night: We've engineered it to  receive us by filling it with light.

    The benefits of this kind of engineering come with consequences 一 called light pollution 一 whose effects scientists are only now beginning to study. Light pollution is largely the result of bad  lighting design, which allows artificial light to shine outward and upward into the sky. III-designed lighting washes out the darkness of night and completely changes the light levels 一 and light  rhythms — to which many forms of life, including, ourselves, have adapted. Wherever human light spills into the natural world, some aspect or life is affected.

    In most cities the sky looks as though it has been emptied of stars, leaving behind a vacant haze(霾) that mirrors our fear of the dark. We've grown so used to this orange haze that the original glory of an unlit nigh, - dark enough for the planet Venus to throw shadow on Earth, is wholly beyond our experience, beyond memory almost.

    We've lit up the night as if it were an unoccupied country, when nothing could be further form the truth. Among mammals alone, the number of nocturnal species is astonishing, Light is a powerful biological force, and on many species it acts as a magnet(磁铁). The effect is so powerful that scientists speak of songbirds and seabirds being “captured” by searchlights on land or by the light from gas flares on marine oil platforms. Migrating at night, birds tend to collide with brightly lit tall buildings.

    Frogs living near brightly lit highways suffer nocturnal light levels that are as much as a million times righter than normal, throwing nearly every aspect of their behavior out of joint including most other creatures ,we do need darkness. Darkness is as essential to our biological welfare, to our internal clockwork, as light itself.

    Living in a glare of our making,we have cut ourselves off from our evolutionary and cultural heritage—the light of the stars and the rhythms of day and night .In a very real sense light pollution causes us to lose sight of our true place in the universe, to forget the scale of our being, which is best measured against the dimensions of a deep night with the Milky Way—the edge of our galaxy arching overhead.

    Do you still remember your favorite poem from high school or some other important periods in your life？Why is it that decades later it still stands out in your mind？Probably the main reason is that some aspects of that poem resonates(引起共鸣)with you．In the same way，you too as a school leader can touch the hearts of your staff and students．

    Poetry allows us to experience strong spiritual connections to things around us and to the past．Thus，it can inspire whatever and whomever it touches．The power that poetry has displayed over time and across cultures actually satisfies this common need of the human heart and soul．

    As one of the oldest art forms，poetry has successfully connected various strands of humanity(人性)from one generation to another．Referring to poetry，Hillyer makes a simple yet meaningful statement，“With this key mankind unlocked his heart．”

    School leaders can find and make use of the value of poetry for themselves，their students and their staff members．Beyond the simple use of poetry，techniques of poetry such as metaphors，repetitions and imagery can be used to take advantage of the power of language to transform communication，create meaning and a culture of care and attention．

    Since schools are mainly about people and relationship，school leaders，like poets，are required to inspire and encourage the human heart．The use of poetry—or even of some techniques of poetry—in school leadership not only helps to improve communication，but also serves to meet the human need for inspiration．

    In the rush to get to school, you drop a piece of toast on the floor. Do you throw it away or decide it's still OK to eat? If you're like most people, you eat it. Maybe you follow the “5-second rule”, which says foods are safe to eat if you pick them up within 5 seconds after dropping them. But you might want to think again. Scientists now say that 5 seconds is all it takes for foods to become polluted with enough bacteria to make you sick.

    Bacteria can cause many kinds of illnesses. Some kinds of bacteria can grow on food. If you eat foods on which these bacteria are growing, you can become sick.

    One of these food-borne bacteria is Salmonella. It makes 1.4 million people sick every year. Salmonella is often found in raw eggs and chicken. Cooking kills these bacteria, which is why it is so important to cook eggs, chicken, and other foods thoroughly.

    But how long does it take these bacteria to pollute food? A team of scientists in South Carolina did an experiment. First, they placed an amount of Salmonella on three surfaces: wood, tile, and carpet. They placed a piece of bread and a piece of sausage on each surface for 5, 30, or 60 seconds. After just 5 seconds, both the bread and the sausage picked up enough bacteria to make you sick.

    So, forget the 5-second rule. If your toast drops on the floor, throw it away and get another piece of clean toast. And next time, be careful not to drop it!

    Cosmetic surgery (整容手术) is not something to be entered into lightly. Unfortunately, in this modern world, we have become confused by very narrow standards of beauty. Images of stars who never seem to age are seen everywhere these days. We forget the fact that most of these images are the result of super photo manipulation (处理), driven by the extremely powerful beauty industry. We are all different — why should we all look the same? Isn't there more to life than having surgery in order to have the same boring face that everybody else wants to have?

—Dr Elisabeth McKenna, Psychologist

    Yes, it's not real! That's what I told my friends when they started asking me about my nose job. I'd always been sensitive to my nose, but it took me a long time before I decided to go for cosmetic surgery. I took advice from several doctors and after careful consideration I finally decided to have it done. I had been saving money from my part-time job and my parents helped me out with the rest. It was quite expensive but I don't regret a penny of it. In fact I wish I'd had it done a few years ago. I' m sure I wouldn't have been laughed at so much at school.

—Debbie Caron, Student

    It makes me really angry to think of the millions of people who spend much money on cosmetic surgery. Surgery should be carried out for medical purposes, not vanity (虚荣心). I would rather all the money spent on cosmetic surgery was used to treat people around the world who are in need but can't get proper medical treatment. Furthermore, there are thousands of under-qualified doctors out there who only care about getting as rich as possible as quickly as possible. They don't care about the psychological and physical damage they do. The whole industry makes me sick. We should do something to stop it.

—Danny Glass, Student

    The world's first subway was built in London in 1863. At the time, the government was looking for a way to reduce traffic problems in the city of London. The poor areas of the city were so crowded with people that it was almost impossible for horse carriages to get through. The city officials were interested in trying to make it possible for workers to live outside of London and travel easily to work each day. If people had a cheap and convenient way that they could depend on to go to and from work, they would relocate their homes outside of the city. This would help ease(减轻) the pressure of too many people living in the poor parts of London. From these problems, the idea of the London Underground, the first subway system, was born.

    The plans for building the Underground met with several problems and delays, but the fast track was finally opened in January 1863. A steam train pulled the cars along the fast underground track which was 6 kilometers (3.7 miles) long. About 30，000 people got on the subway the first day. Riders were treated to comfortable seats (standing up while the train was moving was not allowed), and pleasant decorations inside each of the cars. However, the smoke from the engine soon filled the air in the tunnels(隧道) with ash and soot(煤灰), as well as chemical gases. Fans had to be put in the tunnels later to keep the air clean enough for people to breathe. Even with its problems, riding in the Underground did catch on. It carried 9 million riders in its first year.

    Green is an important color in nature. It is the color of grass and the leaves on trees. It is also the color of most growing plants.

    Sometimes, the word "green" means young, fresh and growing. For example, a greenhorn is someone who has no experience. In the 15th century, a greenhorn was a young cow or an ox whose horns(角)had not yet developed. A century later, a greenhorn was a soldier who had no experience in war. By the 18th century, a greenhorn had the meaning it has today—a person who is new in a job.

    Someone who is good at growing plants is said to have a green thumb(大拇指). The expression comes from the early 20th century. A person with a green thumb can make plants grow quickly and well.

    Green is also the color used to describe the powerful feeling , jealousy(嫉妒). The green-eyed monster （怪物）is not a dangerous animal from outer space. It is an expression used about 400 years ago by the British writer William Shakespeare in his play "Othello". It describes the unpleasant feeling when someone has something he wants. For example, a young man may suffer from the green-eyed monster if you get a pay rise and he does not.

    In most places in the world, a green light means to move ahead. In everyday speech, a green light means agree to continue with a project.