In Asia, there are special competitions where kites have complex designs and are fitted with instruments that make musical sounds as the wind blows through them. Although all kites have a similar structure （结构）, they are widely different in size and shape. Kite-fighting competitions are also held, in which competitions us their kites to attack and bring down their opponents'（对手）kites or cut their strings（线）.

    For more than 15 years, the Big Wind Kite Factory has been giving kite-making and kite flying classes for the children on an island in Hawaii. In its kite-making lessons, students can make kites in as little as 20 minutes! Children as young as four years old can learn how to fly a kite. Jonathan Socher and his wife Daphne started the kite factory in 1980. Their kites are made of nylon（尼龙）.Their designs are Hawaiian themes created by Daphne. The designs are cut out of the nylon with a hot knife that seals the edges and then fastened directly onto the kite. 

    The kite that is used to give lessons is a regular diamond kite with a rainbow pattern. The difference between this kite and the ones they make during the lessons is that it is a two-string controllable kite. Big Wind employees fly the kite and for a few minutes show students how pulling on one line and then on the other controls the direction the kite goes in. Then the controls are given to the students.

    Jonathan insists that it is not necessary to make a huge impressive kite to have fun making and flying kites. Even the simplest structure can work, and can give hours of fun. Go on, give it a try!

    In an unmanned supermarket,a customer waits to pay.With the use of advanced digital payment technology, including biological recognition and in-depth learning,the man leaves in a minute.There's no cashier in the store.At a large university,students use a hand-scanning machine that authorizes their entry into the gym.Those people are using “smart machines” which identify people by their physical characteristics.These new devices use fingers,hands, faces,eyes and voices.Some machines may even use smells.This new technology,called biometrics,gets information from parts of the body.

    In the past,biometric machines were used mainly in government agencies or in prisons.But now that the cost of the technology is lower,these machines are starting to be used everywhere,from border services to schools.

    Some people,however,are concerned that these machines will mean the destruction of personal privacy.They worry that the machines will get personal information about them.“I know it seems like these machines are invading our privacy,but actually,biometric machines help to protect it,”says Jay Tarkett,who works at a company that develops the machines.“They can be used instead of passwords on a computer,for example.They can also identify criminals at airports.So,really,they help to promote public safety,and all the information stored is kept confidential by  the machine itself.”

    Some people don't like the idea of using fingerprints because they associate them with criminals,and feel like they are being accused of something.In addition,they don't work for some people,such as bricklayers,who wear down their fingerprints.Yet,face recognition does work well because the subject doesn't really have to do anything.To cash a check at a bank,for example,the customer has to do nothing more than look at a machine similar to an automatic teller.If the face matches the picture kept on fie,the customer gets the money with no problems.The need to carry identification with you from place to place,then,would all but cease.

    It has been found that the hand scan works well in the college gym.Before this machine was used,students at the college entered the gym using cards similar to credit cards.The problem was that students often lost or forgot their cards.With the hand-scanning machine,however,the problem was solved right away.

    But the machines are still new,and there can be problems.For example,voice recognition works on the phone, but it is not precise,and can be tricked.Another constraint（限制）we notice,with machines that use face recognition in particular,is that they can be fooled if people color their hair or gain a lot of weight.However,this particular problem may be solved by a new type of technology that scans a person's iris,the colored part of the eye.It can even identify the person from a few feet away,recognizing a customer as he or she approaches the ATM.

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To control the nation's growing problem with food wastage, the South Korean government has started a special initiative (倡议) —“Pay as You Trash”. According to the initiative, the South Korean government has three methods in place to charge citizens for the food thrown away. One is through an RFID (Radio Frequency Identification) card — when users tap this card over a specially designed food waste bin, the lid will open. This waste is automatically weighed and recorded in the user's account. The user needs to settle this bill every month.

    The second billing method is through pre-paid garbage bags. These specially designed bags are priced based on the amount of space. For instance, in Seoul, a 10-liter garbage bag costs around 190 won (less than $1). There's also a bar code management system in place, in which residents (居民) throw food waste directly into dustbins and pay for it by buying bar code stickers attached to the bin.

    Even before the pay-by-weight system was introduced, South Koreans were still being charged for food waste — the cost was simply divided equally among the residents of each apartment block. The new system is not only fair, but is also designed to make consumers really feel the pinch of too much waste. The more food they throw out, the more they end up paying.

    Thanks to the initiative, residents like Seoul housewife Ms. Kwan are now adopting creative methods to avoid food waste. She makes sure to pour all the liquid out of leftover food before throwing it away. While preparing vegetables, she tries to use as much as the eatable parts as possible in order to reduce waste.

    Many people believe that you lose the ability to learn new languages as you get older. Language experts, however, will tell you that you're never too old to learn a new language. As you get older, it can be more difficult to learn a new language, though.

    Children and adults learn new languages in different ways. For children, language is their life. They study for thousands of hours every year, because they need to learn languages to become part of their communities. Adults, on the other hand, are already part of a language community. Learning a new language means becoming part of another language community, and adults rarely get the chance to practice as much as young children do.

    Moreover, children learning a new language are expected to make mistakes. This gives them freedom when learning to be daring and confident. Adults, however, often feel pressured to be perfect when learning a new language. This can discourage many people and make it even harder to learn a new language.

    When young children learn a new language, they come to see various languages as a “normal” part of society. This mindset(思维模式) helps them embrace learning a new language without feeling like they're doing something unusual or “too hard”.

    So if you want to learn a new language, go for it! It's never too late to learn a new language. If you're older, it may take more work, but it can be done. If you're a young child, though, now is the time to step out and learn a new language!

    A newly-published study has shown that loneliness can spread from one person to another, like a disease.

    Researchers used information from the Framingham Study, which began in 1948. The Framingham Study gathers information about physical and mental( 心 理 的 ) health, personal behavior and diet. At first, the study involved about 5,000 people in the American state of Massachusetts. Now, more than 12,000 persons are taking part.

    Information from the Framingham Study showed earlier that happiness can spread from person to person. So can behaviors like littering and the ability to stop smoking.

    University of Chicago psychologist (心理学家) John Cacioppo led the recent study. He and other researchers tried to show how often people felt lonely. They found that the feeling of loneliness spread through social groups.

    Having a social connection with a lonely person increased the chances that another person would feel lonely. In fact, a friend of a lonely person was 52% more likely to develop feelings of loneliness. A friend of that person was 25% more likely. The researchers say this shows that a person could indirectly be affected by someone's loneliness.

    The effect was strongest among friends. Neighbors were the second most affected group. The effect was weaker on husbands and wives, and brothers and sisters. The researchers also found that loneliness spread more easily among women than men.

    The New York Times newspaper reports that, on average, people experience feelings of loneliness about 48 days a year. It also found that every additional friend can decrease loneliness by about five percent, or two and a half fewer lonely days.

    Loneliness has been something to do with health problems like sadness and sleeping difficulties. The researchers believe that knowing the causes of loneliness could help in reducing it.

    The study suggests that people can take steps to stop the spread of loneliness. They can do this by helping individuals they know who may be experiencing loneliness. The result can be helpful to the whole social group.

    If we want to find out what kind of technology people used in the past, we normally have to rely on archaeologists to find ruined buildings and parts of tools or instruments or machines. Archaeologists then try to reconstruct, sometimes with the help of computer technology, what these ancient buildings and objects must have looked like, and how they might have been made. Sometimes historians are lucky and find an ancient document with a written description of these ancient buildings and objects.

    We can understand, then, why Chinese historians were so excited when they found cave paintings which show ancient science. They found these paintings in the world-renowned Mogao Grottoes of Dunhuang City, in Northwest China's Gansu Province. There are 500 man-made caves and they have survived for at least 1,600 years. Almost all of these caves have paintings on their ceilings or walls and they date from the 4th to 14th centuries. Wang Jinyu is an expert on these cave paintings (also called frescoes) and he says: "We discovered frescoes containing scientific and technological content in almost all of the caves which have frescoes." What is remarkable about these cave paintings according to the Xinhua News Agency is that they provide evidence of "scientific and technological inventions by ancient Chinese in maths, physics, chemistry, astronomy, geography, agronomy, architecture, textiles, traffic and transportation, arms and military equipment and medical sciences".

    Among the discoveries experts have made are cave paintings showing ancient techniques of pottery making and wine production and paintings showing ancient weaving machines and then toothbrushes! The paintings also give some evidence of the lifestyle at the time with, for example, pictures of people boiling milk over 1,000 years ago. Experts believe that there is more evidence to be found, but even now the caves are a wonderful natural museum. If the walls and ceilings of the caves were all put together they would form a tapestry 20 kilometers long and 2 meters high!

    It won't be possible to travel back in time-that only happens in films-but visiting these caves would be the nearest experience you could get to travelling back in time.