In schools, teachers and pupils alike often assume that if a concept has been easy to learn, then the lesson has been successful.

在学校里，老师和学生都认为如果很容易学会一个概念，那么这堂课就是成功的。

youdao

Experience is a hard teacher. First comes the test, then the lesson.

经验的严厉的导师，首先来自于尝试，其次来自于教训。

youdao

I believe this was a perfect lesson for a child in losing something important...to lose it and feel the full weight of that loss, and then to miraculously get it back.

我相信这是一个完美的教训，对于一个孩子来说，失去重要的东西……失去它，感受到失去的全部重量，然后奇迹般地找回它。

youdao

Partly because there is a widespread view that if caveat emptor should apply to well-heeled lenders to banks, then the lesson has to be taught some time.

BBC: Why Cyprus's rescue matters to us

Our plan was to get there in time for the free group lesson, then to use our new skills to dance the night away.

WSJ: Dilbert Creator Scott Adams's Year Without Fear

The first lesson then is never to surrender or give any quarter to lies.

CENTERFORSECURITYPOLICY: Richard Goldstone and Palestinian statehood