golden rule

详细解释:金科玉律, 指导原则
【法】 金科玉律

英语解释：

名词 golden rule:

any important rulea command based on Jesus' words in the Sermon on the Mount (Matthew 7:12)

例句：

The golden rule in playing tennis is to watch the ball closely.打网球最重要的一点就是紧盯著球。