来自《耶鲁大学开放课程：基础物理 第4集 第4集》

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  And there, by that process, you've gone to higher dimensions.
  按这种方式 我们就进入了更高的维度
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  So let's take again simple problems
  我们一起再从简单的问题开始
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  and try to make them more and more complex.
  然后慢慢研究更复杂的形式
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  And you cannot tell me eventually
  事实上你们不能告诉我说
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  you agree the problem is complex enough,
  这个问题已经够难了
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  or I will crank it up as we go along.
  否则我会加快进度的
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  If at some point you plead for mercy,
  假如什么时候你觉得吃不消了
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  then we'll stop.
  那我们就停下来
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  But there is no limit to how difficult mechanics problems can be.
  但是力学问题可以无止境地复杂深化
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  If you go back and read Cambridge University exams, in 1600 and 1700,
  如果回到十七或十八世纪 去看看剑桥大学的考试
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  there were really difficult problems.
  那才是真正的难题
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  That's why they invented quantum mechanics,
  那就是为什么他们发明了量子力学