书面表达.

      知道火车是由谁发明的吗? 火车是由英国人乔治·斯蒂芬森 (George Stephenson) 发明的.

请根据如下提示写一篇短文. 80词左右. 开头已给出, 不计入总词数.

      提示: do lots of experiments (试验), steam engine (蒸汽机)

     I think the train is one of the greatest inventions in history. Do you know who invented it? Let me tell

 you something about it.___________________________________________________________

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对有限总体只能进行全面调查。（）