草木的阴阳也是平衡的，如果缺少一方就不会繁茂。

采矿业的创新不是可选的-它对我们未来至关重要。

The battle of life is already half won by the young man who is brought personally in contact with high officials; and the great aim of every boy should be to do something beyond the sphere of his duties--something which attracts the attention of those who over him.

形式化方法不是银弹，但它们是追求可靠系统的重要工具。