數(shù)學(xué)的目標(biāo)不是解決問題，而是理解問題。
The world only exists in your eyes. You can make it as big or as small as you want.
The greatest gift you can give someone is your time, because you are giving them a portion of your life that you will never get back.
The defining characteristic of pessimists is that they tend to believe bad events will last a long time, will undermine everything they do, and are their own fault.