习惯是被用来改变的。18世纪中叶,各种瘟疫和灾害导致普鲁士王国农业歉收,上百万人饿死。爱民如子的普鲁士国王弗里德里希大帝听说南美洲有种叫土豆的植物产量高,营养丰富且易于种植,于是决定在全国推广土豆种植。但保守的农民根本不认同,认为地下的东西与鬼神有关,土豆属不吉 Habits are used to change. In the middle of the 18th century, various plagues and disasters led to the poor harvest of the Kingdom of Prussia and millions of people died of starvation. When the Prince of Prussia of Aiminzi Friedrich the Great heard that a plant called a potato in South America had high yields, was nutritious and easy to grow, he decided to promote potato planting throughout the country. However, the conservative peasants did not agree at all, thinking that underground things were related to ghosts and goddesses, and that potatoes were not good enough.