In Philip's case, we ask the question, does he have zero or none zero socks on his feet?

在飞利浦这个例子中，我们就需要判断，他的脚上有没有袜子？

哈佛公开课 - 计算机科学课程节选

So here is an example of socks on feet being 0 the number of socks on Philip's feet which is in fact 0.

因此这里有个袜子在脚上的例子,在飞利浦脚上的袜子数量实际上是。

哈佛公开课 - 计算机科学课程节选