courage, bravery, backbone, nerve
这些名词都可表示“勇气、胆量”之意。
courage : 普通用词。指面对危险或困难时无所畏惧的精神和敢于奋斗的进取心。
bravery : 指在危险中表现出的无所畏惧精神或在逆境中仍能坚持下去的毅力。
backbone : 指性格倔强，意志坚定，有骨气，有顽强的决心去做某事。
nerve : 侧重指面临危险或在冒险的情况下具有冷静、清醒的头脑和坚定无畏的勇气。

幽默故事

  A naval officer fell overboard. He was rescued by a deck hand. The officer asked how he could reward him.

  'The best way, sir,' said the deck hand, 'is to say nothing about it. If the other fellows knew I‘d pulled you out, they‘d chuck me in.'

  最好的奖赏

  一名海军军官从甲板上掉入海中。他被一名甲板水手救起。这位军官问如何才能酬谢他。