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So impressive was this invention, so difficult was it to exceed this speed limit, that nearly 3,500 years later, when the first mail coach began operating in England in 1784, it averaged a mere ten mph. The first steam locomotive, introduced in 1825, could have a top speed of only thirteen mph and the great sailing ships of the time labored along at less than half thatspeed. It was probably not until the 1880's that man, with the help of a more advanced steamlocomotive, managed to reach a speed of one hundred mph. It took the human race millions of years to attain that record.
双轮马拉战车是一项非常突出的发明，要超过它的最高速度实在困难。过了将近3千5百年，到了公元1784年，第一辆邮车在英国运行，其时速平均只有10英里。1825年问世的第一辆蒸汽机车，最高时速仅为13英里，而当时的大帆船仅以不到火车一半的速度在海上慢慢颠簸。大概直到19世纪80年代，人类借助一种更为先进的蒸汽机车，才达到每小时100英里的速度。达到这一记录，人类花了数百万年的时间。
It took only fifty-eight years, however, to go four times that fast, so that by 1938 men in airplanes were traveling at better than 400 mph. It took a mere twenty-year flick of time to double the limit again. And by the 1960's rocket plants approached speeds of 4,000 mph, and men in space capsules were circling the earth at 18,000 mph.
然而，此后只用58年，就把这一速度提高到原先的4倍。到1938年，人们乘坐飞机旅行，时速超过400英里。后来，只用了20年瞬息功夫，这个速度就又翻了一番。到了20世纪60年代，火箭飞机的时速接近4千英里，而人们乘坐宇宙飞船则以1万8千英里的时速绕地球运行。
