I never guess. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.
Learning is not a matter of trial and error, but of insight.
每件事都是一个学习的过程:每次跌倒,都是在教你下次如何站起来。
"The only thing to do with good advice is to pass it on. It is never of any use to oneself."