The art of teaching consists in large part of the ability to awaken the natural curiosity of young minds and to satisfy it with the nourishment of knowledge.

It has been said that man is a rational animal. All my life I have been searching for evidence which could support this.

人们雕刻东西，如果半途而废，即使是腐烂的木头也不能刻断；如果坚持到底，即使是金属或者石头都能雕空。