Mathematics is not a careful march down a well-cleared highway, but a journey into a strange wilderness, where the explorers often get lost.
登山不因为艰难险峻就停止攀登，那么最终必定能登上峻岭。
The greatest virtue in life is real courage that knows how to face facts and live beyond them.
Silence is a virtue, but silence in front of someone you like is cowardice.