有时，你必须回头看，才能理解前方的事物。
"Sometimes, you have to look back in order to understand the things that lie ahead."
"Sometimes the smallest things take up the most room in your heart."
数学的目标是理解我们观察到的现象背后的结构。
To be happy, I must have my books and a piece of sky.
Leadership means making tough decisions today for a better tomorrow.
如果你每天都履行自己的义务，你就不必担心未来。