No way to retrieve it.

也没有办法找回。

耶鲁公开课 - 死亡课程节选

So it doesn't matter how big the dictionary is, you can instantaneously retrieve the value associated with the key. Extremely powerful.

因为你可以在线性时间，内得到想要的键对应的值,这太强大了。

麻省理工公开课 - 计算机科学及编程导论课程节选

And I do that very precisely because it'll teach you a little bit about how easy or difficult it is to do it and what kind of information you retrieve from a dietary assessment.

我这样要求是因为,这能教给你,做评估的难易程度,以及你们能从饮食评估中得到何种信息

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选