从幼年初期时起，我们就与我们的计数系统紧密联系在一起，以至于考虑未开发计数能力的早期人类所面临的那些问题，就已经成为了想象力上的一次壮举。

From earliest childhood, we are so bound up with our system of numeration that it is a feat of imagination to consider the problems faced by early humans, who had not yet developed this facility.

youdao

语言在我们的注意力上占了很大的因素。

Words are powerful factors in regards to our focus or lack thereof.

youdao

所以我们决定集中在我们的核心竞争力上。

So we decided to focus on our core competency.

youdao

That means the force you're applying is cancelled by another force, which has got to be the force of friction.

意味着你施加在物体上的力被另一个力抵消了,这个力就是摩擦力

耶鲁公开课 - 基础物理课程节选

There, Newton doesn't tell you what forces are going to be acting on a body in a given situation.

在式子里,牛顿没有告诉你,在给定条件下,有哪些力,作用在物体上

耶鲁公开课 - 基础物理课程节选

So, if we think about the force that occurs between a positively and a negatively charged particle, what we have is essentially a Coulomb force, so we can describe this as a force of attraction.

一个带负电的粒子之间，的作用力,这本质上就是库伦力，我们可以把它，描述成一个引力。

麻省理工公开课 - 化学原理课程节选