Why do Americans like to use pencils?

The same problem bothered me for a week, so I bought three brands of pencils, Chen Guang, Kyle and Fa Brigas. There is not much difference between the three kinds of pencils except their appearance and hardness. Of course, high-end pencils have never been used, after all, they are expensive. But I didn't feel anything special when I used a pencil. Later, the secret was discovered by accident. Let me talk about my views on this issue, which is also speculation. I have been using American textbooks recently, such as Thomas Calculus and Princeton Calculus. It is often said that learning can be done by drawing, whether by hand or by computer, and it has been said many times. The way these textbooks impart knowledge is different from that in China. Books are very thick, and they all start with very simple things. I don't even want to read the first 50 pages. Obviously, things in college are as simple as those in our junior high school. But after half a book, it will become particularly profound. No matter how simple and difficult it is, the way has not changed, that is, theorem, proof, formula and drawing. Almost every formula or theory involved is always explained by graphics. After discovering this rule, I downloaded several textbooks of other subjects and found the same thing. Interested students can go to Netease to watch the calculus video of MIT, and have talked about the importance of drawing many times. If you look at their teaching methods, you will find that Americans are very stupid. Teacher China recited a formula and knew the result. I will give you proof and inference. Sorry, I don't have time. I think this is because Americans have been educated in different ways and ways of thinking since childhood, and they have to draw everything they learn. After all, drawing pencils is the most convenient. If you make a mistake in a complicated picture in class, you must correct it. If you use another pen, you have to use correction fluid or something (thinking of the taste of correction fluid and the sound of clicking correction), but it is not as convenient as pencil correction. And from the perspective of environmental protection, pens and pencils are the most environmentally friendly. The casing of fountain pen is mostly plastic, which was basically burned by garbage incineration plant. Now, it is impossible to classify all garbage in detail. The pollution caused by plastic burning is far more than sawdust. The writing length of an HB pencil is almost less than that of a fountain pen. There is also the stability of the pencil, and many materials can be written on the surface. Why do Americans use pencils to draw pictures? They are used to it.