我知道，有个道理你们已经听过成千上万次了。但那是真的：艰辛的工作带来回报。如果你希望好起来，你就必须练习、练习，再练习。
It was the best of times, it was the worst of times.
People fear what they don't understand and hate what they can't conquer.
The aim of art is to move the heart.
In mathematics, as in life, the most elegant solutions often arise from a deep understanding of the problem.