You may think that light pollution isn't something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment that light pollution does. But light pollution is serious.

    Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago. Light pollution is the light that comes from streetlights, buildings, parking lots and any other source of light that is reflected or directed into the atmosphere.

    Urban light pollution means that one-fifth of the world's population can no longer see the Milky Way(银河) with the naked eye(肉眼). Many city kids, even if they did look through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our  night-time environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks.

    Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid a brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings(孵化的幼仔)may confuse over-lit beachfront resorts(度假胜地) for the ocean horizon, wasting precious energy needed to find the sea and escape predators(食肉动物). Because their necks aren't yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The bright lights can blind them, leading to countless collisions with buildings and other tall structures.

    On an individual level, people can help reduce much sky glow by using lighting only when necessary. The stars above us are priceless heritage— for not only for astronomers but for all humans. More of our children should be able to look up at night and see the Milk Way.

    The winter vacation is just around the corner. With such a long holiday to spend, have you decided where to get yourself relaxed from the great pressure of school study? Our company specializes in civil tours. We take pride in offering you the best services and in providing you with a vacation that will be fondly remembered. The following places can be your unforgettable destinations in our country.

    A. The Australian Museum

    The Australian Museum has an international reputation in the fields of natural history and indigenous studies research and exhibitions. The museum was established in 1827 and is Australia's first museum of natural science and cultural artifacts.

    B. Sydney Olympic Park

    Home of the Best Games Ever and 2003 Rugby World, Sydney Olympic Park is a gold medal attraction and continues to serve as a major sport and social venue.

    Apart from its ultra-modern sport venues, Sydney Olympic Park is set in extensive parklands. Bicentennial Park, one of Sydney's most popular recreational areas, is criss-crossed with walking and bicycle tracks.

    C. Art Gallery of New South Wales

    Located within a short walking distance from Sydney's CBD, the Art Gallery of New South Wales is one of Australia's foremost art museums housing some of the finest works of art in the country.

    The Gallery has a rich and diverse collection including key works of the Heidelberg School and favorite modern Australian artists including Brett Whiteley and Margaret Preston, as well as permanent Australian, European, Asian, contemporary and photographic galleries.

    D. Koalas Park Sanctuary

    Koalas are on show every day. Shows are at 10:20 A.M., 11:20 A.M., 2:00 P.M., 3:00 P.M. where you can cuddle, feed, pat and have your photo taken with the Koalas. See free roaming Koalas as well, 10 acres of rainforest. Walk in and pat our kangaroos.

    Are you preparing for a big test? If so, you may want to go play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels, including those in the brain, stronger and more fully developed. Dr. Cameron claims this allows people who exercise to concentrate better. As she says, “While we already know that exercise is good for the heart, exercise can really cause physical changes in the brain.”

    The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results. Margaret Barnes, a pediatrician（儿科医生）, believes in the importance of exercise. She thinks that many learning disabilities that children have in elementary school or high school can be traced back to a lack of movement as babies. “Babies need movement that stimulates their five senses. They need to establish a connection between motion and memory. In this way, as they get older, children will begin to associate physical activity with higher learning,” says Margaret.

    Older people can strengthen their brains as well. Columbia University studied a group of seniors ranging in age from seventy to seventy-nine. Their study showed a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for older people should involve some complexity. Learning some new skills or motions, such as with yoga or tai-chi, helps to open up memory paths in the brain that may not have been used for a long time.

    For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain's flow of blood. And your brain can benefit from as little as three to four hours of exercise a week.

    On a recent afternoon, some 60 years after they graduated from grammar school, Kathleen Rys, 72, and her sister Lorraine O'Kelly, 70, sat down and had a meal with a classmate, Bruce Smit, 71 for the first time.

    In the 1950s, Lorraine and Kathleen Rys' family moved from Chicago to Monee. As new kids at Monee Elementary School, they soon found themselves on the outs with other students.

    "I would be with the other guys and see Kathleen walking down the hallway, her head down, holding her books, walking slowly. And all of us guys would be flat against the wall until she passed. Then we'd burst into laughter. How rude is that? It's just crazy." said Smit, a doctor whose wife, Tammy, organized the meeting.

    The women said none of the teachers cared about it. "We just kept it to ourselves. " Lorraine said.

    Over the years, Tammy Smit said, "Bruce would just start to cry at times. He'd wonder what happened to the sisters, if they landed OK." One day a few weeks ago, Tammy took to the internet and found Mary O'Kelly, Lorraine's daughter, and offered to set up a meeting. The idea of revisiting the pain was not well- received by Kathleen, who had never married, let alone gone on a date. It took some convincing, but Lorraine finally got Kathleen to agree to meet with Bruce.

    Bruce broke into tears. "I'm so ashamed, so embarrassed," he said. "But I'm so happy you're still here and that I can finally apologize. " He said he hopes his apology will encourage others to seek forgiveness for the pain they make on others. Lorraine said, "This is a beautiful thing. It's just wonderful that a person from 60 years ago can ask for forgiveness. It's like a miracle to us. It's a healing to us."

    In the book The Best Little Girl in the World, Kessa has a serious eating disorder (进食障碍) called anorexia nervosa. But she is not alone. Many people have this eating disorder.

    In the beginning of her story, Kessa is a normal 15-year-old girl. She is good at many things, especially dancing. She has danced for many years and loves it. One day her dance teacher tells her to continue eating right, but maybe lose a few pounds. Once Kessa hears this, she takes things too far. Instead of cutting down on snacks and junk food, she decides not to eat at all. She does not eat breakfast, lunch, or dinner. She begins losing weight and becomes slimmer (更加苗条的) and slimmer. But she loses weight to a point where she is unhealthy.

    As her poor eating habits continue, her parents start getting as much help as possible to cure (治疗) their beautiful daughter. But it is just as hard for Kessa's parents to deal with her disorder as it is for her.

    Every day she exercises to lose more pounds and plans what and when she will eat. Her parents try everything, but Kessa decides not to have any fat on her body.

    Kessa's doctor and parents finally take her to the hospital. She is now so thin that she can hardly walk. There, she is given good care.

    In the rest of the book, Kessa goes through a lot of trouble in order to cure her eating disorder. This book, I think, can help to prevent people from doing this to themselves. It shows the trouble that people go through just to be slimmer, and all the terrible things they must experience to be cured. It is a book I think every teenager should read.

    Fire fighting is a serious matter. Knowing what to do during a fire can save people's lives. It is important to know the ways you can use and show them to everyone else in the family, such as stairways and emergency exits, but not elevators.

    From the lower floors of buildings, escape through windows is possible. Learn the best way to get out from a window with the least chance of serious injury.

    The second floor window is usually not very high from the ground. An average person, hanging by the fingertips will have a drop of about 6 feet to the ground. It is about the height of an average man. Of course, it is safer to jump a short way down than to stay in a burning building.

    Windows are also useful when you are waiting for help. Be sure to keep the door closed before opening the window. Otherwise, smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get fresh air rather than smoke that may have leaked(漏)into the room.

    On the second or third floor, the best windows for escape are those which open onto a roof. From the roof a person can drop to the ground more safely. Dropping onto cement might end in injury. Bushes and trees can help you to have a soft landing.