没有人能在相当长的时间内，对自己戴一副面孔，对众人戴另一副面孔，而最终不困惑于哪一副才是真实的。
No man, for any considerable period, can wear one face to himself and another to the multitude, without finally getting bewildered as to which may be the true.
The most important thing in mathematics is to understand the concepts, not just to memorize formulas.
Number is the ruler of forms and ideas， and the cause of gods and daemons.
Something does not need to be perfect to be wonderful. Especially weddings.
"The best ideas come from the people closest to the problem."