思想需要书来磨砺,正如宝剑需要磨刀石。
A mind needs books like as word needs a whetstone.
In mathematics, the simplest explanation is often the most profound.
诗歌是灵魂的语言,是无形之物的声音。
除非有勇气远离海岸,否则你永远游不到新的地平线。