They say it takes some training. And there can be risks, like running when your feet are too cold to feel if you get injured.

VOA: special.2010.02.03

You might be winded doing it the second way, but when you get to the top and you are at the 60th story your gravitational potential is independent of how you got there.

对于走路你可能很抓狂，但你一旦到了顶层,你就是在第60层,你的重力势能,与你如何到达那里无关。

麻省理工公开课 - 固态化学导论课程节选

The way he described is when you try to get down a quantum dimensions and you are standing there with your camera, just remember the sun is at your back and your shadow is always in the picture.

这种方法被他描述为,当你试着处理一个量子尺寸时,并且你试着拿着你的相机在那，记住太阳在你的背后,而你的影子总是在照片上。

麻省理工公开课 - 固态化学导论课程节选

When you retire--you can actually get it now, electronically, your entire employment history, all your contributions-- when you retire, there will be a formula-- you can find it on the Social Security system website-- which resembles the formula that they did in 1889.

现在你退休之后可以自动得到，你这一生的工作情况，还有你全部的投保记录-,当你退休的时候-,你可在社会保障体系网站上找到一个公式-,类似于1889年使用的那个公式。

耶鲁公开课 - 金融市场课程节选