True happiness arises, in the first place, from the enjoyment of one's self, and in the next, from the friendship and conversation of a few select companions.

The greatest mistake you can make in life is to be continually fearing you will make one.

Immediately pay what you owe to vendors， workers， contractors. They will go out of their way to work with you first next time.

数学不是一项观赏性运动。

仅靠技术无法拯救我们；它必须与我们消费和思考能源方式的根本转变相结合。