You see you cannot tell the height or the depth rather of a pool based on the average.

只知道平均值,并不知道游泳池的水深。

哈佛公开课 - 幸福课课程节选

Then it lands on your foot, because assuming the cannon is at zero height, the cannonball certainly comes out towards the enemy, but has no time of flight.

然后它就会落在你的脚边,因为假设大炮的高度为 0,炮弹笔直地出膛打向敌人,却没有时间飞行

耶鲁公开课 - 基础物理课程节选

Imagine I have a little lamp, a little goose- one of those little gooseneck lamps, I'd put it on the table here, I'd put the height about a f-- about a foot off the table. And if I was really good, - I could hit, or time it so that when I hurt- yeah, try again. When I turn this on switch on in the lamp, at exactly the same time, I'm going to hit a key on my computer and start it running.

想象下我有一个那种小雁颈台灯-,我把它放在桌子上，大概离桌子，有一英尺那么高吧,这样挺好的，我可以打开-,或者关闭这灯,并在这同时，我可以让我电脑,开始运行。

麻省理工公开课 - 计算机科学及编程导论课程节选