Erm, I know, er, let's do the Latin declension song.
明白了 我们来唱拉丁变格歌。
It was natural, therefore, that the sovereigns of those countries should be particularly attentive to the interests of agriculture, upon the prosperity or declension of which immediately depended the yearly increase or diminution of their own revenue.
因此,这些国家君主很自然地应该特别关注农业利益,农业繁荣或退直接取决于他们每年收入增加或减少。