but there are several points

但幻灯片上列出的几点
where you could look at the slides and confirm that some of the things

可以帮助大家理解和确认
I'm going to tell you are actually true.

我下面要讲的知识的正确性
And I want to give you three examples.

我将为大家列举三个例子
One is color.

一个是颜色
And I'm going to conflate here color and brightness.

我打算把颜色和亮度放在一起讲
The other is object.

一个是物体
The other is depth.

还有一个是深度
First, the problem of color.

首先是颜色的问题
How do you tell a lump of coal from a snowball?

你如何才能区分出煤球和雪球呢
Well, that's a lump of coal

那是一个煤球
and that's a snowball,

而那是一个雪球