摘要：铅笔是我们生活中十分常见的物品,常见到我们甚至很少会注意到它。其实,小小铅笔的背后有着不少故事,看完这篇文章之后,你或许会对它'另眼相看'。On March 30,1858,inventor Hymen L.Lipman patented the first pencil with a built-in eraser—then sold it for$100,000.