Books are the quietest and most constant of friends; they are the most accessible and wisest of counselors, and the most patient of teachers.
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。
The true test of a mathematical idea is its ability to inspire further questions.
The essence of learning is the acquisition of meanings.