次要规则是那些规定主要规则的创建、修改和废止的规则。

最优货币区是指能够以最小的实际经济干扰来稳定就业和价格的区域。

To be Irish is to know that in the end, the world will break your heart.

I think that the best thing that you can do is to be true to yourself and to be honest with yourself.

【释义】：圣人处世的道理是灵活多变的，能根据时机和环境变化而采取合宜的行动，不拘泥于固定的方式。