我如何知道是否有真正的物体存在呢？

How do I know that there is a real physical object?

youdao

我如何知道椅子是存在的？

How do I know that there are chairs?

youdao

你想问的是，我如何知道它是和等高线垂直的吗？

Do you mean how do I know that it is perpendicular to a level curve?

youdao

Because I really want to understand what it is like for a son and a father to relate each other.

因为我很想让知道,一对父子,是如何默契相连的。

麻省理工公开课 - 媒体、教育、市场课程节选

In other words, now I know how to tell how the Helmholtz free energy changes as a function of temperature.

换句话说，我现在知道如何写出亥姆赫兹,自由能作为温度的函数。

麻省理工公开课 - 热力学与动力学课程节选

What have we done over the last three or four lectures? We've started introducing you to classes of algorithms. Things that I'd like you to be able to see are how to do some simple complexity analysis.

我们在过去三节或四节课中讲了什么？,我开始向你们,介绍算法的类型,我想你们知道的是,如何做一些简单的复杂度分析。

麻省理工公开课 - 计算机科学及编程导论课程节选