老脑筋就像老马；如果你想保持它们的工作状态，你必须锻炼它们。
Old minds are like old horses; you must exercise them if you wish to keep them in working order.
数学是一种超越文化和语言障碍的通用语言。
The general will is always right， but the judgment which guides it is not always enlightened.
You can’t change the people around you, but you can change the people you choose to be around.
In productive thinking, the transition from blind manipulation to understanding is crucial.