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磁悬浮列车

    上海磁悬浮列车专线全长29. 863公里,2003年1月4日正式通车,全程只需8 min,如图甲所示。上海磁悬浮列车上装有车箱线圈,铁路底部则安装轨道线圈。通电后,轨道线圈产生的磁场极性与列车车箱线圈的极性总保持栩同,两者“同性相斥”,在磁力的作用,将列车浮起10 mm左右。此时的磁力与列车本身的重力相互平衡,使列车悬浮在轨道上运行,这必须精确控制电磁铁的电流,如图乙所示。

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    I had just arrived in this Asian country for a one-year teaching position. One day, I took the subway to visit some ancient palaces and temples in the downtown. The following account of what happened to me has taught me much about culture 1.

    Since all the 2 were taken, I stood. Suddenly, I felt someone pulling on my bag. 3 I probably was in someone's way, I moved over slightly. But in one quick motion(动作), I felt my bag removed from my back, and in a flash it was 4. I turned around to see who the thief was. I looked at the people standing behind me, but didn't see my bag or any 5. My heart sank and I began to 6.

    I glanced around the car only to find directly across from me was an elderly lady, and sitting on her lap was my 7. I tried to get it back from her lap. But as I began to 8 it up, she quickly grabbed(抓住) it back and held onto it. I looked around at the people standing beside me, and those sitting beside her, but no one took any 9 of the situation. Trying not to cause a(an) 10, I tried to negotiate through gestures. I used my hands as best as I could, but she 11 my requests for my bag and pointed to my back. She picked up my bag, showing how 12 it was. I finally began to understand. She was holding my bag to13 me.

    At the next stop, a middle-aged woman got on the crowded subway. Another elderly woman sitting down took her bag, 14 it on her lap. They didn't talk; 15 this older woman was more than pleased to sit with this stranger's bag on her lap throughout her journey.

    As the subway pulled into the main downtown station and I was getting ready to get off, the woman 16 handed me back my bag. But 17 I had a chance to thank her, she had disappeared into the crowd.

    Sadly, this considerate custom was more 18 to me than if I had been robbed. Everyone back home had heard of being robbed—that was 19 city behavior—but having a stranger hold onto someone's bag out of 20, in a city of twelve million people—that was truly unusual.