记得我在读初中的时候,初接触几何学上的反证法,不好领会,甚至感到乏味、枯燥,到头来就无精打采了。那时在旁的父亲(也是一个教育工作者)见此情形,若有所思之后,给我看一个古代的故事: 王戎七岁,尝与小儿游。看道旁李树多子折枝,诸儿竞走取之,唯戎不动。人问之,答曰:“树在道旁而多子。此必苦李。” I remember when I was in junior high school, early contact with the geometry of the anti-card law, poorly understood, and even boring, boring, eventually lethargy. At that time, the father (who is also an educator) was looking at this situation. After thinking for a moment, he showed me an ancient story: Wang Rong was seven years old and tasted traveling with children. Look at the roadside tree plum branch, all children race to take it, only Rong does not move. People ask, answered: “The tree in the road and more children. This will bitter Lee.”