But very soon will you find that if you're writing programs with lots and lots of functions, and some might call these, and these might call these, you can come up very soon with scenarios where you can not order them top to bottom, because everything is comingled, and there's a lot of cross talk among all of your functions.

但是不久后你们会发现你们写的程序中,有很多很多的函数，有的函数调用这些函数，这些函数又调用另外的函数，你不能用脚本,把它们从上到下排序，因为所有函数相互混合,在你的函数中也有很多交叉。

哈佛公开课 - 计算机科学课程节选

It's a more powerful method than something called a cross-sectional study, and I'll come back in a later lecture and talk about these in more detail, but a cross-sectional study means you're taking a snapshot of a population of people at one time.

这种方法比所谓的横断面研究更加有效,我将在以后的课中,再仔细讨论这个问题,但横断面研究是指,你一次记录下一群人的状况

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选