种一棵树最好的时间是20年前，第二好的时间是现在。
In mathematics, as in life, the most elegant solutions often arise from a deep understanding of the problem.
As to the gods, I do not know whether they exist or not, nor what they are like in form; for there are many things that hinder sure knowledge, the obscurity of the matter and the shortness of human life.
The pursuit of knowledge is a never-ending journey, and each discovery opens the door to new questions.