Whenever there is a force, it can be traced back to a tangible material cause, which is all the time a force of contact, with the exception of gravity.

如果有作用力,那它一定能找到一个明确的实体施力物体,也就是无论何时物体受的都是接触力,引力除外

耶鲁公开课 - 基础物理课程节选

If you're expecting to be attacked and besieged, as all these citadels would be by an invader, you would want more than anything else a water supply, but they didn't necessarily have good water supplies in such circumstances.

如果你预料到会被攻击和包围,就像这些城邦面对侵略者那样,你最关心的一定是水源供应,但在这样的情况下,他们未必能找到充足的水源

耶鲁公开课 - 古希腊历史简介课程节选

I digressed a little from this diagram but I think you've gotten the picture that as I move to more adult organisms, as I move to more specific regions of the brain, for example, I can still find progenitor cells that have some potential.

我不太认同这张图表,不过我认为随着我说到成人机体,你们已经在脑海中有这样的概念了,我在更特异性的区域,比如大脑中,仍能找到有一定潜能的祖细胞

耶鲁公开课 - 生物医学工程探索课程节选