I have no idea what's here at the moment so I'm just going to draw a question mark because that memory might have been used previously for some other purpose, but we know it's currently available to us so we have four bytes of memory.

我不知道在此刻这里是什么,所以我画一个问号，因为那块内存可能在之前,为其它的目的而使用过，但是我们知道它可以为我们所使用,这样我们就有4个字节的内存。

哈佛公开课 - 计算机科学课程节选

The mathematical theory of probability was unknown until that time and you can see that insurance suddenly made an appearance at that time.

在那之前,概率的数学理论,是不存在的,而随着概率论的出现,保险业也突然出现了

耶鲁公开课 - 金融市场课程节选