Habit is habit, and not to be flung out of the window by any man, but coaxed downstairs a step at a time.
You have to be comfortable with being uncomfortable if you want to make progress in mathematics.
The only way to know your limits is to go beyond them.
采矿业是周期性的,但伟大的公司是由那些既能驾驭低迷期又能驾驭繁荣期的人建立的。