论文部分内容阅读
铅笔不含铅着实是因为历史造成的误会。古希腊、罗马曾用金属铅制成类似铅笔的铅棒。14世纪,欧洲出现类似现在的铅笔。1565年,
Pencil lead is really because of historical misunderstanding. Ancient Greece, Rome used metal lead made of lead-like pencil. In the 14th century, a pencil similar to today appeared in Europe. In 1565,