一台传真机看上去是在传送一张张纸，但实际上它是用电话将物体的影像（比如说文字）从一台传真机传送到另一台上。我们可以想象一篇文章上的文字被划分为成千上万个微小的点，当你将这页纸送入传真机中，传真机就移动一束微小的光线一行一行地扫描它。对于每个微小的点，... A fax machine appears to send a sheet of paper, but it actually telephony transfers the image of an object (say text) from one fax machine to another. We can imagine that the text in an article is divided into thousands of tiny dots. When you load the page into a fax machine, the fax machine moves it with a small amount of light and scans it line after line. For each tiny point, ...