Darek Fidyka, a 38-year-old Bulgarian, had been paralyzed (瘫痪的) from the chest down for four years after a knife attack. Scientists from Britain and Poland took cells from his nose, transplanted (移植) them into his back and re-grew his spinal cord (脊髓). Now he can walk and even drive a car. The doctors were delighted but said it was the first step in a long journey.

    The breakthrough came after 40 years of research by Professor Geoff Raisman, who found that cells had the possibility to repair damage to nasal (鼻腔的) nerves, the only part of the nervous system that constantly re-grows. “The idea was to take something from an area where the nervous system can repair itself and put it into an area that doesn't repair itself,” Professor Raisman said.

    Polish doctors injected (注射) the nasal cells into Mr Fidyka's spinal cord above the injury and used some nerves from his ankle to form a bridge across the damaged tissue. The nasal cells appear to have caused the spinal nerves to repair themselves.

    Professor Raisman achieved this with rats in the late 1990's, but this is his greatest success. “I think the moment of discovery for me was Christmas in 1997 when I first saw a rat, which couldn't control its hand, put its hand out to me. That was an exciting moment, because I realized then that my belief that the nervous system could be repaired was true.”

    Doctors chose the easiest case for their first attempt—it might not work for others. But there is a real sense of hope that an idea once thought impossible has been realized.

    David Nicholls, who helped provide money for the breakthrough, said information about the breakthrough would be made available to researchers across the globe.

    “What you've got to understand is that for three million paralyzed people in the world today, the world looks a totally brighter place than it did yesterday,” he said.

    Technology is the application of knowledge to production. Thanks to modern technology, we have been able to increase greatly the efficiency of our work force. New machines and new methods have helped cut down time and expense while increasing overall output. This has meant more production and a higher standard of living. For most of us in America, modern technology is thought of as the reason why we can have cars and television sets. However, technology has also increased the amount of food available to us, by means of modern farming machinery and animal breeding techniques, and has made our life span longer via medical technology.

    Will mankind continue to live longer and have a higher quality of life? In large measure, the answer depends on technology and our ability to use it widely. If we keep making progress as we have over the past fifty years, the answer is definitely yes. The advancement of technology depends on research and development, and the latest surveys show that the united States is continuing to put billions of dollars annually(每年) into such efforts. So while we are running out of some limited resources, we may well find technological substitutes (代用品) for many of them through our research programs.

    Therefore, in the final analysis, the three major factors of production (land, labor and capital) are all influenced by technology. When we need new skills or techniques in medicine, people will start developing new technology to meet those needs. As equipment proves to be slow or inefficient, new machines will be invented. Technology responds to our needs in helping us improve our standard of living.

    For most city people, the elevator is an unremarkable machine that inspires none of the enthusiasm or interest that Americans afford trains, jets，and even bicycles. Dr. Christopher Wilk is a member of a small group of elevator experts who consider this a misunderstanding. Without the elevator, they point out, there could be no downtown skyscrapers or tall buildings, and city life as we know it would be impossible. In that sense, they argue，the elevator's role in American history has been no less significant than that of cars. In fact, according to Wilk_? the car and the elevator have been locked in a “secret war” for over a century, with cars making it possible for people to spread horizontally (水平地)，and elevators pushing them toward life in close groups of towering vertical (垂直的)columns.

    If we tend to ignore the significance of elevators, it might be because riding in them tends to be such a brief, boring, and even awkward experience^one that can involve unexpectedly meeting people with whom we have nothing in common, and an unpleasant awareness of the fact that we're hanging from a cable in a long passage.

    In a new book, Lifted, German journalist and cultural studies professor Andreas Bernard directed all his attention to this experience, studying the origins of elevator and its relationship to humankind and finding that riding in an elevator has never been a totally comfortable experience. “After 150 years, we are still not used to it”， Bernard said. “We still have not exactly learned to cope with the mixture of closeness and displeasure.” That mixture, according to Bernard, sets the elevator ride apart from just about every other situation we find ourselves in as we go about our lives.

    Today，as the world's urban population explodes，and cities become more crowded, taller, and more crowded, America's total number of elevators—900,000 at last count, according to Elevator World magazine's “2012 Vertical Transportation Industry”一are a force that's becoming more important than ever. And for the people who really, really love them, it seems like high time that we looked seriously at just what kind of force they are.

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   The English are often described as unfriendly people who don't talk to strangers (陌生人). But not London taxi drivers. I once asked one cabby to describe his life to me and he didn't stop talking until I arrived home half an hour later. He told me many interesting stories and this is one of them.”Some strange things happen late at night. The other day I was taking a woman home from a party. She had her little dog with her. When we got to her house, she found that she'd lost her key. So, I waited in the cab with her dog while she climbed in through the window.”

    “I waited and waited. After hour of ringing the bell I decided to find out what was going on. I tied the dog to a tree and started to climb in through the window: The next thing I knew was that the police came. They thought I was to rob the house! Luckily, the woman came downstairs. She'd gone to sleep and forgotten about me and the dog. I was in such a hurry to get away that I forgot to ask her for the fare.”

    Most people have flown a kite or have seen one ride and dip in strong spring wind. Not so many people know that kites were first made in China thousands of years ago. The ancient Chinese were making and flying kites even before they were writing.

    A long time ago, the Chinese made kites to use in wars. They would fly these war kites in the dark. The kites were fixed so that they made strange sounds. Men who were at war with them would hear these sounds and run away. They thought those strange sounds were made by gods in the sky.

    The ancient Chinese also flew kites to bring good luck and to make their crops grow rich and tall. Sometimes they tied long strings and hooks to their kites. Then they would fly the kites over water, letting the hooks hang down to catch fish.

    The Chinese use sticks, strings and paper for their kites. Some of these kites look like animals or trees. Others look like birds or houses.

    "Have a nice day！" may be a pleasant gesture or a meaningless expression. When my friend Maxie says "Have a nice day" with a smile, I know she sincerely cares about what happens to me. I feel loved and safe since another person cares about me and wishes me well.

    "Have a nice day. Next！" This version of the expression is spoken by a salesgirl at the supermarket who is rushing me and my groceries out the door. The words come out in the same tone (腔调) with a fixed procedure. They are spoken at me, not to me. Obviously, the concern for my day and everyone else's is the management's attempt to increase business.

    The expression is one of those behaviors that help people get along with each other. Sometimes it indicates the end of a meeting. As soon as you hear it, you know the meeting is at an end. Sometimes the expression saves us when we don't know what to say. "Oh, you just had a tooth out? I'm terribly sorry, but have a nice day. "

    The expression can be pleasant. If a stranger says "Have a nice day" to you, you may find it heart­warming because someone you don't know has tried to be nice to you.

    Although the use of the expression is an insincere, meaningless social custom at times, there is nothing wrong with the sentence except that it is a little uninteresting. The salesgirl, the waitress, the teacher, and all the countless others who speak it without thinking may not really care about my day. But in a strange and comfortable way, it's nice to know they care enough to pretend they care when they really don't care all that much. While the expression may not often be sincere, it is always spoken. The point is that people say it all the time when they like.