The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.

语言不仅仅是交流的工具，更是精准的武器。

解释：脚力不强劲，行程就不会远；刀刃不锋利，割东西就不会深。

教学应服从于人类心智发展的规律。