阅读理解
The pencil is a very simple object. However, it took hundreds of people over centuries to what make it what it's like today.
The story of the pencil starts with graphite(石墨). People cut it into small sticks and use them to write or draw. Around 1560, an Italian couple named Simonio and Lyndiana Bemacotti added wood holders to the graphite sticks. However, since the graphite is too soft, the pencils were easy to break. In 1795, in France, Nicolas-Jacques Conte worked out a method of mixing graphite powders with clay(黏土). In this way, people made strong pencil core（铅笔芯）, To this day, the method is still used in making pencils.
It was Henry David Thoreau who came up with the grading scale(分级量表) for different hardnesses of pencils. It was graded one through four, and grade two is the proper hardness for general use. The softer the pencil is, the more graphite it has in it, and the darker the line is. The harder the pencil is, the more clay it has, and the lighter the line is. Nowadays, pencils marked 2B are usually used in exams to mark answers. Pencils marked HB are usually daily writing. People usually use pencils of different hardness and blackness to draw different parts of a picture.
When pencils were handmade, they were made round. Then an American Joseph Dixon developed machines to make pencils. Later people found out it was easier and less wasteful to make a pencil which has six sides.
There is a pencil for everyone and every pencil has a story. The Blackwing 602 is famous for being used by a lot of writers. And then, you have the Dixon pencil company. It's what people think of when they think of a pencil and what they most probably will buy when their children are about to write.
In my opinion, there's nothing that can be done to make the pencil better than it is.