To live remains an art which everyone must learn,and which no one can teach.
生活是一种人人须学而无人能教的艺术。
You must be the best judge of your own happiness.
当今的科学家们思考得很深,而不是很清晰。一个人必须头脑清醒才能清晰地思考,但一个人可以思考得很深却相当疯狂。
追求知识是一段没有终点的旅程。