Given the abstraction, the notion of a point as an instance with some values, I can now start building segments.

真的很有帮助，基于这个抽象,点的概念也就是一个，有一些值的实例。

麻省理工公开课 - 计算机科学及编程导论课程节选

And then from that start point, get the x-value. Same thing, from that instance, get the endpoint, from that end point get the x-value, square.

取得结束点，然后取得结束点的y坐标，然后求差开平方，然后同样求的y坐标。

麻省理工公开课 - 计算机科学及编程导论课程节选

It says if I want to get the length of a segment, going to pass in that instance, it says from that instance, get the start point, that's the thing I just found.

它的意思是如果我想要,得到一个线段的长度，首先要把这个实例传进来，然后对于这个实例，从开始点，取得x坐标，然后通过同样的操作。

麻省理工公开课 - 计算机科学及编程导论课程节选