书籍是最安静、最恒久的朋友；它们是最易接近、最睿智的顾问，也是最耐心的老师。
"Books are the quietest and most constant of friends; they are the most accessible and wisest of counselors, and the most patient of teachers."
The deterioration of every government begins with the decay of the principles on which it was founded.
The Erdős discrepancy problem fascinated me because it was so simple to state yet so deep in its implications.