Neither the life of an individual nor the history of a society can be understood without understanding both.
数学中发现的快乐是无与伦比的。
过去是一个异国,那里的人做事方式不同。
可持续发展不仅仅是一种趋势,而是我们对后代的责任。
Mental processes exist because they have served life's continuance.