For example, let's take the case where the particle is falling under gravity.

比如说,举个例子,一个质点正在重力的作用下下落

耶鲁公开课 - 基础物理课程节选

I won't sing for you or give you my Italian, but these famous lines, "London Bridge is falling down, falling down, falling down" and so on, these come from the conclusion to The Waste Land.

我不会给你唱出来或者秀我的意大利文，但是这些著名的词句，“伦敦桥在倒塌“,“在倒塌，在倒塌“，以及种种，这些是从《荒原》的结束语中来的。

耶鲁公开课 - 现代诗歌课程节选

And this is useful because if you're actually writing a program that's interactive or that you want to change overtime much like you would a game, hopefully, the game is not going to have the bad guys, for instance, always standing in the same place or the rocks or whatever it is falling from the sky in the same place 'cause it would very quickly become a very tedious game.

这是很有用的，因为如果,写一个交互的程序或者,希望每次游戏都不一样，我们希望，游戏中的坏人物，别老是站在同一个地方或者同一块石头上,或者从天空中同样的位置落下,因为这立刻会使游戏变得乏味。

哈佛公开课 - 计算机科学课程节选