Those nonprofits learned a painful lesson: Attempting to start an unrelated business venture means they were hit with a double whammy.

这些非营利组织学到了痛苦的一课：尝试非营无关业务意味着他们腹背受敌。

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Bezos warned that the gift of creativity was a double-edged sword that could lead to complacency and worse, a know-it-all attitude, a lesson that he candidly admits he learned the hard way.

贝佐斯警告毕业生们，创造力是一把双刃剑，可能使人自满，甚至导致更加糟糕的结果——令人自以为无所不知，他坦言自己也是在历经艰辛之后才明白了这个道理。

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Lesson 11, down a minute, class takes double power.

课上落下一分钟，课下需花双倍功。 翵。

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The metaphorically-minded Mr. Eliot would be pleased to know that his famous phrase provides a double lesson for presenters.

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But he did learn a valuable lesson: Double-check the serial number on the box.

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As I noted in my recent trading lesson, the Spyder Trust ( SPY) had two sharp double-digit rallies in 2012, but each was followed by almost a double-digit correction.

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