来自《耶鲁大学开放课程：新生有机化学 第5集 第5集》

• 
  
  Okay, and turn this one off.
  好了 现在把灯关了
• 
  
  Okay. Now I'll show you first what we're going to do.
  现在我来告诉大家首先做什么呢
• 
  
  So pull out the little thing there.
  把屏幕放这
• 
  
  And there's a laser that's focused right here,
  有一束激光点在这里
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  but it's too bright, because
  但是它太亮了 因为
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  the other things we're going to see are very dim,
  其他的东西显得比较暗
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  which is why we had to turn the lights off.
  由于我们把灯关了
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  So I'm going to put this black tube there,
  那么我会把这个黑色管子放这
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  with a little hole in the end.
  管子底下是有个洞的
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  Hopefully I can get it positioned
  希望能把位置放对
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  so that most of the laser will go inside here
  这样激光就能穿过管子
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  and we won't see it very well.
  我们才能看到它