The state of your life is nothing more than a reflection of your state of mind.
我总是很高兴地想到,我的教育大部分是非正式的,并且根植于土壤之中。
The time which we have at our disposal every day is elastic; the passions that we feel expand it, those that we inspire contract it; and habit fills up what remains.
The essence of mathematics lies in its freedom.