New York's iconic, blue-green statue of liberty wasn't always green. When the statue was gifted to the US from France in 1885, she was actually a shiny copper color. A new video reveals the chemical reactions involving oxygen and even air pollution that led to her color change from copper to liberty green. The statue of liberty was a gift from France to the US as a way of commemorating the US's fight for independence, as well as their own aspiration for democracy.

    A video, published by the American Chemical Society, explains that the 305-foot (93 meter) statue was built over nine years in sections of copper skin on top of an iron skeleton.

    In her first few decades in the Big Apple, the statue slowly turned from that shiny copper color to a dull brown and the, finally, to the blue-green, or as they'd say back in France, 'verdigris' we see today,' said the video's narrator.

When it changed color, some officials suggested restoring her back to her original color, but after the public protested against this decision, she was left the way she is. The statue's color change was as a result of oxidation reactions between copper and the air. But it was more than one reaction - the color change is due to about 30 years worth of different reactions leading to a mixture of greenish minerals.

    Oxidation reactions happen when an atom loses an electron to another atom.

    In the case of the statue of liberty, her color change was bound to happen due to oxygen in the atmosphere that is 'hungry' for electrons. On top of this, elements of New York City's polluted air added to the color change too.

The first chemical reaction of the color change involved copper giving up electrons to electron-hungry oxygen in the atmosphere. This led to a mineral called cuprite - which is pinkish red.

    Then, cuprite loses even more electrons to oxygen, forming a new mineral（矿物质） called tenorite, which is blackish in color. The black color of tenorite explains why the statue got darker over time, forming a dark brown color.

    Then, further chemical reactions occurred when sulfur（硫） in the atmosphere reacts with oxygen to form sulfur dioxide. Sulfur comes from natural processes such as volcanic eruptions, but also from man-made emissions from boats, cars, airplanes and factories. When sulfur dioxide in the atmosphere reacts with water, it produces sulfuric acid. Sulfuric acid forms green minerals with copper oxides, so the sulfuric acid in the atmosphere made the state green over time.

    Added to that, chloride from the sea spray surrounding Ellis Island where the statue is located made the statue even greener.

    The statue stayed this way for over 100 years because the exposed copper is now oxidized and stable, but the statue wouldn't be the same anywhere else.

How can I fight laziness?

    Lazy people will never amount to anything in life. However, laziness can be defeated once a few changes have been made in your mind.

    {#blank#}1{#/blank#}Many people lack sleep constantly, since they stay up too late and get up too early to prepare for work. These people have little motivation once they arrive home. Laziness works hand in hand with a lack of motivation and a tendency to put off things. By adjusting your sleep schedule to provide a few more hours of meaningful rest, you can fight laziness throughout the day.

    Another way to fight laziness is to change your mind from passive to active. Some people treat their lives as if they were pushed from task to task. Others take a more proactive approach, viewing each task as a challenge they must overcome alone.{#blank#}2{#/blank#}

    Some people fight laziness by removing the temptations that surround them. A television in the living room may provide entertainment, but watching too much TV often contributes to laziness. Create a reward system for yourself, just as parents do for a child to promote responsibility.{#blank#}3{#/blank#}

    {#blank#}4{#/blank#}Spouses and children may all have different energy levels, but laziness can be spread if not dealt with immediately. To fight household laziness, lead by example. Be the first to collect and wash dishes after a meal. Others in the home may eventually follow your example and perform their own task. It is difficult to practice laziness when your are surrounded by motivated people.

    {#blank#}5{#/blank#}Enough exercise and a balanced diet can help you to develop a healthy lifestyle, thus enabling you to have more energy and help lift your spirits.

A. Knowing how to fight laziness is important.

B. One way to fight laziness is to get enough sleep.

C. Laziness can also be a lasting problem at home.

D. Complete a few tasks and reward yourself with what you enjoy, such as a good dinner or a film.

E. Finally, taking exercise regularly can help you fight laziness.

F. With strong determination, you will be able to achieve your goal.

G. Laziness sets in when you no longer feel in charge of your own life.

    Feifei, an 11-year-old boy from Xuzhou, Jiangsu Province, suffered from a sudden acute eye disease which has almost led to blindness. The disease was caused by excessive(过度的)eye fatigue(疲劳)during the winter vacation, during which he played computer games for continuous 10 days and nights.

    Many youngsters in China nowadays are increasingly addicted to computer games and other electronic products. This is followed by a series of health problems, with the most typical case being myopia, or nearsightedness.

    According to the latest research report released by the World Health Organization (WHO), the myopia   rate among Chinese teenagers ranks first in the world—70 percent of high school and college students. The rate is nearly 40 percent in primary school students, while it is only 10 percent for their peers in the United States.

    There are at least 10 million people in China with severe myopia, and they are likely to get pathological(病理性的)myopia in middle age. Pathological myopia can't be treated with glasses or surgery, and it is one of the biggest factors that lead to blindness, Xu Xun, director of the ophthalmology(眼科学) department at Shanghai General Hospital, pointed out.

    Experts explain that two major factors lead to the high rate of myopia among Chinese people. One is high academic pressure, and the other one is excessive use of electronic devices over a long period of time. Genetics, on the other hand, are not the main reason, as only 20 percent of Chinese people had myopia in the 1960s.

    "Teenagers are now faced with severe academic pressure, which means they often study without natural light. This increases their risk of becoming nearsighted," Xu said.

    Experts suggest that youngsters maintain a proper balance between study and rest so as to protect their eyesight, and parents should play an active role in the process.

    Next month, I'm traveling to a remote area of Central Africa and my aim is to know enough Lingala — one of the local languages — to have a conversation. I wasn't sure how I was going to manage this — until I discovered a way to learn all the vocabulary I'm going to need. Thanks to Memrise, the app I'm using. It feels just like a game.

    "People often stop learning things because they feel they're not making progress or because it all feels like too much hard work," says Ed Cooke, one of the people who created Memrise. "We're trying to create a form of learning experience that is fun and is something you'd want to do instead of watching TV."

    Memrise gives you a few new words to learn and these are "seeds" which you plant in your "greenhouse". When you practice the words, you "water your plants". When the app believes that you have really remembered a word, it moves the word to your "garden". And if you forget to log on (登录)，the app sends you emails that remind you to "water your plants".

    The app uses two principles about learning. The first is that people remember things better when they link them to a picture in their mind. Memrise translates words into your own language, but it also encourages you to use "mems". For example, I memorized motele, the Lingala word for "engine", using a mem I created — I imagined an old engine in a motel (汽车旅馆) room.

    The second principle is that we need to stop after studying words and then repeat them again later, leaving time between study sessions. Memrise helps you with this, because it's the kind of app you only use for five or ten minutes a day.

    I've learnt hundreds of Lingala words with Memrise. I know this won't make me a fluent speaker, but I hope I'll be able to do more than just smile when I meet people in Congo. Now, I need to go and water my Vocabulary!

    As the days get shorter and the chilly weather rolls in, we all want to curl up in a blanket and hibernate until spring rolls around. But making time to get outside in the sun, even when it's cold out, could have bigger mood benefits than you might realize.

    While the link between sunshine and mental health is nothing new, new research from Brigham Young University (BYU) has shown that the association may be even stronger than previously realized. It finds that sunlight exposure is by far the greatest weather-related factor determining mental health outcomes. In other words: more sunshine, more happiness.

    For the study, a psychologist, a physicist and a statistician from BYU teamed up to compare daily environmental data from the university's Physics and Astronomy Weather Station with emotional health data archived by day for 16,452 adult therapy patients who were being treated at the BYU Counseling and Psychological Services Center.

    Exposure to sunlight is a significant factor in seasonal affective disorder. Research has shown that the brain produces more of the feel-good neurotransmitter serotonin on sunny days than it does on darker days. What's more, lack of sunlight is linked with lower vitamin D levels, which in turn has been correlated with depression and low energy.

    If you're getting enough sun, your emotions should remain relatively stable, the researchers found. But as the amount of sunlight in the day is reduced, levels of emotional pain can soar. Other weather variables including temperature, pollution and rain were not found to have an impact on mental health.

    “We were surprised that many of the weather and pollution variables we included in the study were not significantly correlated with clients' scores on the distress measure once we had accounted for suntime," Dr. Mark Beecher, a professor of psychology at the university and the study's lead author, told The Huffington Post. “People tend to associate rainy days, pollution, and other meteorological phenomena with sadness or depression, but we did not find that.”

    Every student has his/her own style of studying and it's up to you to use the available resources to be as effective and productive as possible. Here are some tips on how to study effectively.

    ● Know yourself. When determining the best approach, you need to assess your personality. Some people can read for hours while others can't sit still through more than one chapter. Find your pace, improve it and work around your strengths and weaknesses.

    {#blank#}1{#/blank#}If you prefer being alone, learn to study by yourself.

    ●Set a goal. {#blank#}2{#/blank#}It'll not only help you keep focused and stay on track, but it'll also help you organize your time and activities.

    ●Learn over time. It's impossible to learn a lot of things in a short time. If you don't know or understand the lesson from the start, you won't get it the night before your big test. {#blank#}3{#/blank#}

    ●{#blank#}4{#/blank#}Allocate(分配) your time between studying and other activities. Create a routine schedule for your studying time. Strictly follow this schedule so as to develop an effective studying session.

    ●Have time to rest. It's necessary to have enough time to rest in order to regain all the energy used up by the body from all the studying. {#blank#}5{#/blank#}Communicate with other people and participate in recreational activities to help you relax and refresh your mind.

    Following the tips above, you can easily have your way of studying effectively!

A. Have good study habits.

B. Set a realistic and reasonable schedule.

C. Try to discover the type of reading that best suits you.

D. Your mind won't be so sharp if you don't have enough sleep.

E. You need to determine what you want to achieve in a given subject.

F. If you need other people to help you, get a tutor(家教) or join a study group.

G. It's best to study smaller loads of information repeatedly over a period of time.