Courage勇气
Mark Twain

　　又谈到勇气了。的确，听到勇气这个词，大家会不由得振奋起来。但勇气是个相对的概念，人有的时候面对死亡会大无畏，而在另一些情况下，比如说看到一只老鼠，会吓得面色苍白，浑身发抖。那么能说这个人没有勇气吗？本文作者马克．吐温先生在他的演讲中以极其幽默的口吻为我们阐释了这一点。让我们随他去体会"勇气"的内涵吧！

In the matter of courage we all have our limits. There never was a hero who did not have his bounds. I suppose it may be said of Nelson and all the others whose courage has been advertised that there came times in their lives when their bravery knew it had come to its limit.
I have found mine a good many times. Sometimes this was expected -- often it was unexpected. I know a man who is not afraid to sleep with a rattle-snake, but you could not get him to sleep with a safety-razor.

* Bounds："界限"、"范围"、"止境"等意思，There is no bounds to his foolishness（他的愚蠢无止境）。Out of bounds to表示"禁止入内"。看来，英雄们的勇气也是有止境的。
* Rattle-snake：在美语里也写作rattler，是"响尾蛇"的意思。Rattle-snake原产于美洲，因发怒时尾部会有响声而得名。
* Safety-razor："安全剃刀"、"保险剃刀"。这个人敢睡在响尾蛇旁边，却不敢睡在剃须刀旁边，可见，"勇气"是个很奇怪的东西，它没有绝对的标准。 　　

I never had the courage to talk across a long, narrow room. I should be at the end of the room facing all the audience. If I attempt to talk across a room I find myself turning this way and that, and thus at alternate periods I have part of the audience behind me. You ought never to have any part of the audience behind you; you never can tell what they are going to do.
I'll sit down.

* Alternate："轮流的"、"交替的"等意思，由此，大家肯定可以猜出alternating current表示"交流电"。由alternate这个词我们可以想象作者站在听众中间，担心背后的人会做什么的不安的样子。