He learned this lesson the hard way – from his own personal experience.

他惨痛地得到了这一教训–从他自己的亲身经历中得来的。

《柯林斯英汉双解大词典》

We must keep this lesson in mind.

我们要记住这个教训。

《新英汉大辞典》

Never forget this lesson.

永远不要忘记这个教训。

《新英汉大辞典》

Farmers learn this lesson tragically sometimes when their animals feed on wild plants.

VOA: special.2009.08.25

Now if you can just persuade the English and Portsmouth soccer players of this lesson, I'd be very happy.

现在如果你能让英格兰或者朴茨茅斯球员,学会这个规律的话,我会非常高兴的

耶鲁公开课 - 博弈论课程节选

But bad things will start to happen if I don't mind this lesson of indexing.

但是坏事情将发生,如果我不注意索引的教训。

哈佛公开课 - 计算机科学课程节选

Officials think the markets are strong enough to take this lesson in creditor responsibility.

BBC: Lessons of Cyprus

The Concorde partners learned this lesson 27 years, and lots of taxpayer money, too late.

FORBES: Beware Of The Concorde Fallacy

Everyone from the President of the U.S. on down can benefit from this lesson.

FORBES: Talking Too Much? Maybe Not!