And the problem is, that we want to build this abstract data type, but we'd like to basically know what kind of object is it, and what functions actually belong to it, how do we use them?

然后我对它们运行了这个方法，就是这一小段代码这个方法,这有意义么？,当然没有了，对不对？,因为你知道，当你把两个极坐标，表示的点进行相加运算的时候？

麻省理工公开课 - 计算机科学及编程导论课程节选

Here's another problem that I'd like to solve.

那么我们已经看过了这样的一个例子了。

麻省理工公开课 - 计算机科学及编程导论课程节选

The big problem life insurance had was people would buy it and they'd pay for several years and eventually they would think, well we didn't die, we're losing all this money, let's just cancel the insurance.

人寿保险的一个主要问题是,人们在购买了若干年保险后会突然觉得,我们并没有死,保费白花了,我们干脆把保险取消好了

耶鲁公开课 - 金融市场课程节选