儿童对活动的需要几乎比食物的需要更为强烈。
仓库里空虚了日子就会难,子孙愚笨了怎么知晓礼义呢?
就好像让人伏在剑刃上,而期望他能长寿一样。 
The beauty of science lies in its ability to explain the natural world.