解释：货卖完了才知道不足，是由于不懂得计量；事情结束了才知道有余，是由于不懂得调节。

Art should comfort the disturbed and disturb the comfortable.

The true test of civilization is not the census, nor the size of cities, nor the crops, but the kind of man that the country turns out.

编写无错误程序的方式有两种：只有第三个有效。