Because if you did what I suggested with the list, the time to look up the key would be linear in the length of the list. You'd have to look at each element until you found the key.

字典是用一种很神奇的，叫做散列法的算法,来实现的，后面我们将,会学到一点关于。

麻省理工公开课 - 计算机科学及编程导论课程节选

Second, I'd like to identify two key questions that I really think important for you to be thinking about and addressing in the area of new technology and education.

接着确定两个关键问题,这两个问题很重要,你们要好好想想怎样,在新技术和教育中定位。

麻省理工公开课 - 媒体、教育、市场课程节选

If we could get clear about what the answer to that metaphysical question the key to personal identity we'd at least know what we needed to find out to answer the question: ? Is this one person or two?

如果我们能知道,那个形而上问题的答案,对于人格同一性的关键,至少我们会知道,我们要知道什么来得出答案：,是同一个人还是两个人？

耶鲁公开课 - 死亡课程节选

And they got in this habit of, every time they had a bright, happy text, they'd set this in one kind of mode or key-- a major mode--and every time they had a sad one, they'd set it in minor.

于是人们养成了这样的习惯,每当人们书写欢乐,愉悦的歌词时,他们就设定一个调式或调性,即大调,每当人们书写忧伤的歌词时,他们就定为小调

耶鲁公开课 - 聆听音乐课程节选