I came to study in the United States a year ago. Yet I did not know the real American society until I was injured in a car accident because after the accident I had to see a doctor and go to court.   

    After the accident, my roommate called a doctor for me. I was very grateful and determined to repay him one day. But the next day, he asked me to pay him $200 for what he had done. I was astonished. He had good reason to charge me, he said. And if I wanted to collect money from the person who was responsible for my injury, I'd have to have a good lawyer. And only a good doctor can help me get a good lawyer. Now that he had helped me find a good doctor, it was only fair that I should pay him.  

    But every day I went to see the doctor, I had to wait about 50 minutes. He would see two or three patients at the same time, and often stop treating one so as to see another. Yet he charged me $115 each time. The final examination report consisted of ten lines, and it cost me $215.    

    My lawyer was all smiles the first time we met. But after that he avoided seeing me at all. He knew very well the other party was responsible for the accident, yet he hardly did anything. He simply waited to collect his money. He was so irresponsible that I decided to dismiss him. And he made me pay him $770.    

    Now I had to act as my own lawyer. Due to my inexperience, I told the insurance company the date I was leaving America. Knowing that, they played for time and I left without getting a cent.

    Hummingbirds(蜂鸟) are one of nature's most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.

    Now scientists have found that it is the ratio(比值) of the bird's wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.

    David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink's team used the same machine to test the blades from an advanced micro-helicopter used by the UK's army. They found that the micro-helicopter's blades are as efficient at hovering as the average hummingbirds.

    But while the micro-helicopter's blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird's wing. The wings of Anna's hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter's blades.

    While Professor Lentink wasn't surprised at nature's superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it's amazing that we're getting closer. It's not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”

    Professor Lentink said that we don't know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.

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    Gift buying for 11 to 14-year-olds can produce memories of that classic complainer. “This gift is too old.” “This gift is too young.” “This gift was popular, like, five minutes ago.” Don't stress. Our fun gifts are sure to make you smile.

—Judy Sutton Taylor

    Snowball Launcher

The kids on your list will be happy to drop their electronic devices and head outside during the next big snowstorm thanks to this gift that launches snowballs up to 70 feet. A practice target is included to ensure they're ready for a hard battle. $16.97 at amazon.com

    Nintendo Switch

    Gamers went crazy for this mixed gaming system when it was released last spring, and it was in consistently short supply until now. The device allows users to play solo or with a friend, connect it to a TV to play on a big screen, unfold the stand for tabletop competitions, or use it for hand-held play. $299.99; links to licensed retailers at nintendo.com or amazon.com

Mertritte Animal Headphone

    Tunes will no doubt sound sweeter to lovers of any music genre when they5re coming from these cute-as-can-be headphones designed by celebrity stylists Emily Current and Merritt Elliott. The gold finish adds some fun flare (闪光装置) that is sure to inspire copycats. $59 at pbteen.com

BBOP Balls

    If there's a more entertaining way to settle sibling differences than having warring brothers and sisters bump into each other putting on mega-sized bubble armor (盔甲), we'd like to know about it. Chances are, even what may seem like the most catastrophic conflicts will end in belly laughs after a few rounds wearing these. $69.98 for a set of two at hearthsong.com or amazon.com.

It's long been thought that in order to succeed in life you need to think only of yourself and ignore the needs of others. New research,however,suggests the exact opposite is true and being nice to others actually makes you more likely to be successful. The scientists found that ‘givers' were more likely to share knowledge,and in turn gain more information themselves.

    Researchers divided participants into three groups based on a personality test: givers, takers and matchers. In a social dilemma task, participants were given a made-up donation which was equal to the amount of ￡ 240( $400). They were then asked to decide how much of their money they would give to a shared group pool. They were told that the money in the pool would be doubled and divided equally among all group members. Thus,it would be more beneficial to the group as a whole if everyone contributed their individual donations. However, it would be more beneficial for the individual if everyone else from the group contributed,while the individual kept his or her own money. The researchers used this strategic (策略的) information sharing task to examine how much and which pieces of information participants shared:the less important and already known information or the really important information only known by the individual.

    The results showed that givers are less self-centered and self-loving than takers. Givers shared not only more money with the group, but they also shared important information. Takers on the other hand kept both the money as well as different types of information.

    The findings suggest that it may not be enough to simply provide knowledge management tools in order to make the best of knowledge exchange in a group of people. It may be necessary for leaders and managers to keep in mind the personality styles of their employees. Specifically, they should be aware that takers may keep the important information for themselves.

    Humans are social animals. They live in groups all over the world. As these groups of people live apart from other groups, over the years and centuries they develop their own habits and ideas, which are different from other cultures. One important particular side of every culture is how its people deal with time.

    Time is not very important in nonindustrial societies. The Nuer people of East Africa, for example, do not even have a word TIME that is in agreement with the abstract thing we call time. The daily lives of the people of such nonindustrial societies are likely to be patterned around their physical needs and natural events rather than around a time schedule(时间表)based on the clock. They cook and eat when they are hungry and sleep when the sun goes down. They plant crops during the growing seasons and harvest them when the crops are ripe. They measure time not by a clock or calendar(日历), but by saying that an event takes place before or after some other event Frequently such a society measures days in terms of "sleeps" or longer periods in terms of "moons." Some cultures, such as the Eskimos of Greenland measure seasons according to the migration of certain animals.

    Some cultures which do not have a written language or keep written records have developed interesting ways of "telling time". For example, when several Australian aborigines want to plan an event for a future time, one of them places a stone on a cliff or in a tree. Each day the angle of the sun changes slightly. In a few days, the rays of the sun strike the stone in a certain way. When this happens, the people see that the agreed-upon time has arrived and the event can take place.

    In contrast(成对比), exactly correct measurement of time is very important in modern, industrialized societies. This is because industrialized societies require the helpful efforts of many people in order to work. For a factory to work efficiently(well, quickly and without waste), for example, all of the workers must work at the same time. Therefore, they must know what time to start work in the morning and what time they may go home in the afternoon. Passengers must know the exact time that an airplane will arrive or depart. Students and teachers need to know when a class starts and ends. Stores must open on time in order to serve their customers. Complicated(复杂的)societies need clocks and calendars. Thus, we can see that if each person worked according to his or her own schedule, a complicated society could hardly work at all.

    Researchers in Australia have discovered an effective new method to capture the atmospheric carbon dioxide that is damaging our planet and transform it into something solid, making it much easier to store.

    Carbon capture isn't new, but previous methods call for the gas to be compressed into liquid and then injected underground. Widespread usage of that technology has been locked by economic and environmental concerns due to possible leaks. Instead, in a study published in Nature Communications, the group details their sustainable and cost-effective plan for transforming CO₂ into coal.

    This new process involves a liquid metal catalyst(催化剂)that is efficient in conducting electricity. CO₂ gas is dissolved in a container with some liquid. Once electricity charge is introduced, the CO₂ begins to turn into solid pieces of carbon, which can be collected and stored.

    What makes this particularly unique is that the entire process can occur at room temperature. Previous experiments have only shown a gas to solid conversion at extremely high temperature, which made it impossible on a large scale. Now, the researchers are hoping that their work will be used to create even further when it comes to carbon storage.

    In an interesting side benefit, the solid carbon also works as an electrode(焊条), which opens up a world of possibilities. "A side benefit of the process is that the carbon can hold electrical charge, becoming a super battery, so it could potentially be used as a part in future vehicles," explains Dr. Dorna Estrafilzadeh, a researcher. "The process also produces fuel as a by-product, which could also have industrial applications."