The guzheng is a traditional Chinese musical instrument. It belongs to the zither（齐特琴）family of string instruments. It is the parent of many musical instruments of some other countries.

    The guzheng should not be confused with the guqin, another ancient Chinese zither but without bridges. Now the guzheng is zither with movable bridges and usually 21 strings, although it can have from 15-25 strings. The guzheng's strings were formerly made of silk, though most players used metal strings by the 20^th century. Since the mid-20^th century most performers use steel strings. The guzheng has a large resonant cavity（共振腔）.

    The guzheng has existed since the Warring States Period and became especially popular during the Qin dynasty. The number of strings on the guzheng has always fluctuated. There were as few as 6 to as many as 23 strings during the Tang dynasty. The earliest record of the guzheng belonged to the historian Sima Qian. Until 1961, the common guzheng had 16 strings, although by the mid-20^th century 18-string guzheng were also in use. In 1961, Xu Zhenggao, together with Wang Xunzhi, introduced the first 21-string guzheng after two years of research and development. In 1960, they also invented the “S-shaped” left string rest, which was quickly adopted by all guzheng makers and is still used today. This curve allows for greater ease in tuning the strings and, combined with strings of different thickness, allows for greater resonance in both the deeper and the higher pitch（音调）ranges. The 21-string guzheng is the most commonly used one, but some traditional musicians still use the 16-string one.

    In the near future, we may be using our eyes to operate our smart-phones and tablets, even when it comes to playing popular games like Fruit Ninja.

    The Gaze Group has been developing eye-controlled computer technology for nearly 20years. But those devices have been firstly designed to help those with disabilities, and are very expensive.

    “After a while, we figured out that probably the best way is to go for a mass-market way,”says Gaze's Sune Alstrup Johansen. “Where everybody would have this available.”

    Johansen and some of his colleagues have formed a new company, the Eye Tribe, which is hoping to develop the technology on a mass commercial level.

    The technology works when combined with the computing device toward the user's face. After making sure of the user's eye movements, the technology is then able to easily find where a person's eyes are moving, and then allow the eyes to control a cursor (光标)

    “Our software can then determine the location of the eyes and know where you're looking on the screen to make sure what you're looking at, ”reads an explanation on the Eye Tribe site.

    There has been a gradual change toward hands-free technology in recent years, particularly in the gaming world. Recently Xbox released the Kinect device, which lets users control their Xbox and play certain games using only their hands, legs and voices. But still, most of these devices have been more of a gimmick than a practical way to use one's hands to control a mobile device. Johansen said a replaceable filter (滤光器) would be a cheap, convenient way for most consumers.

    And even as companies like The Eye Tribe work to create such a product for the average user, making the eye-controlled technology more accessible and less expensive will have similar benefits for physically disabled users.

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    There are some strange driving laws in different countries.

    Skiing has always been a big part of Kamikaze shiffrin's life. Her dad ski raced all through college and her mom raced and coached skiing. The Siffrins taught Mikaela and her brother, Taylor. To ski at a very young age. At two and a half years old, Mikaela made her first ski run down her driveway on plastic skis.

    Mikaela loved skiing. From ages 8 to11, she did hundreds of training runs on small hills to learn the skills of slalom skiing (障碍滑雪). When Mikaela was 11, she began to learn at the Burke Mountain Academy, a Vermont boarding school for skiers. She took classes, studied, and practiced her skiing. According to Burke Mountain Academy headmaster Kirk Dwyer, "What separated Mikaela from others was the degree of her commitment (投入) to be the best. Mikacla practiced more than anyone and believed in herself then and now." At age 14, Mikaela began her international career when she raced in the world championship for13 and 14 -year-olds. And she won!

    By the time she was17, she had already won her first World Cup race. "Living away from home four and five months at a time can be difficult" Mikaela says. "But it can also be exciting. I'm getting to see the world." When Mikaela began ski racing in Europe, her mother, Eileen, stayed with her. She worked as her high school teacher while they were on the road. "She has always been a super-hard worker," says Eileen.

    For Mikaela, working hard is a full-time job. Even her off-season is work time. "If you want something, just try your best," she says. At the 2014 Winter Olympic Games in Sochi, Russia, 18-year-old Mikaela Siffrin became the youngest slalom skier ever to win an Olympic gold medal.

    If you're a fan of smart technology, you may have had some sleepless nights lately. That's because Alexa, the artificial intelligence (AI) behind US company Amazon's Echo smart speakers, has been "letting out an unprompted (自发的),creepy (令人毛骨悚然的)cackle for no apparent reason, according to BBC News.

    Many social media users shared their stories of Alexa scaring them with the seemingly unprompted laugh.

    "Every time Alexa laughs, an angel dies," Tesla and SpaceX founder Elon Musk joked on social media.

    On March 7, Amazon released an update that fixed the problem, saying that the laugh was caused by Echo devices mistakenly thinking that users had said the command " Alexa, laugh".

    However, what should have been a funny story raised the ongoing topic of man versus machine.

    With the rise of artificial and robotic technology, "Digital machines started to demonstrate broad abilities in pattern recognition, complex communication, and other area that used to be particularly human," wrote Erik Brynjolfsson and Andrew McAfee in their book The Second Machine Age: Work, Progress, and Prosperity in a Time of Brilliant Technologies. They believe that AI will "do more and more, and our lives will get better".

    However, ever since the earliest days of AI there have been concerns that some day, software will take over the world, leaving the fate of humans unknown.

    "With artificial intelligence we are order the demon (魔鬼)Musk told students during a meeting at MIT in 2014. "If I had to guess at what our biggest existential threat is, it's probably that. So we need to be very careful

    Many scientists have shared the same concern. The late British physicist Stephen Hawking said at a technology conference in Portugal in November that "computers can. in theory, imitate human intelligence, and exceed it ••• AI could be the worst event in the history of our civilization."

    If creators are to safely control AL however, Hawking suggested that they "employ best practice and effective management".

    I am an optimist and I believe that we can create AI for the good of the world," he said at the conference. "We simply need to be aware of the dangers, identify them, employ the best possible practice and management, and prepare for its consequences well in advance."

    Recently, as the British doctor Robert Winston took a train from London to Manchester, he found himself becoming steadily angry. A woman had picked up her phone and begun a loud conversation, which would last an unbelievable hour. Furious, Winston began to tweet about the woman. He took her picture and sent it to his more than 40,000 followers.

    When the train arrived at its destination, Winston rushed out. He'd had enough of the woman's rudeness. But the press were now waiting for her on the platform. And when they showed her Winston's messages, she used just one word to describe Winston's actions: rude.

    Winston's tale is something of a microcosm(缩影) of our age of increasing rudeness, fueled by social media. What can we do to fix this?

    Studies have shown that rudeness spreads quickly, almost like the common cold. Just witnessing rudeness makes it far more likely that we, in turn, will be rude later on. The only way to avoid it is to deal with it face to face. We must say, "Just stop." For Winston, that would have meant approaching the woman, telling her that her conversation was frustrating other passengers and politely asking her to speak more quietly or make the call at another time.

    The rage and injustice we feel at the rude behavior of a stranger can drive us to do odd things. In my own research, surveying 2,000 adults, I discovered that the acts of revenge people had taken ranged from the ridiculous to the disturbing. Winston did shine a spotlight on the woman's behavior — but from afar, in a way that shamed her.

    We must instead combat rudeness head on. When we see it occur in a store, we must step up and say something. If it happens to a colleague, we must point it out. We must defend strangers in the same way we'd defend our best friends. But we can do it with grace, by handling it without a trace of aggression and without being rude ourselves. Because once rude people can see their actions through the eyes of others, they are far more likely to end that strain themselves. As this tide of rudeness rises, civilization needs civility.