毁于一旦 ruined in an instant
Explanation
指由于某种原因，之前积累的东西一下子全都没了，常指心血、成果等。
Refers to the fact that due to some reason, what has been accumulated before is gone at once, often referring to painstaking efforts and achievements.
Origin Story
话说唐朝时期，有一个名叫李白的书生，勤奋好学，十年寒窗苦读，终于考取了进士功名。他满怀喜悦，带着十年寒窗苦读的成果——满满一箱的书籍和笔记，准备启程去长安赴任。然而，一次意外的风波，让他的梦想毁于一旦。途中，暴风雨突袭，他的船只遭遇了不幸，所有装载书籍和笔记的箱子，都被倾倒入江中，泡烂了。十年寒窗苦读的心血，就这样毁于一旦，李白伤心欲绝，唯有望江兴叹。他只好回到家乡，重新开始他的科举之路。
In the Tang Dynasty, there lived a scholar named Li Bai, who was diligent and studious. After ten years of hard work, he finally obtained the title of Jinshi. Filled with joy, he set off for Chang'an to take up his post, carrying the fruits of his ten years of hard study—a full box of books and notes. However, an unexpected incident ruined his dream. A sudden storm struck, and his boat was wrecked; all the boxes containing books and notes were overturned and soaked in the river. The fruits of his ten years of study were thus destroyed. Li Bai was heartbroken, could only lament by the river. He returned to his hometown and had to start his career path again.
Usage
多用于书面语，形容事物彻底毁灭。
Mostly used in written language, to describe the complete destruction of something.
Examples
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多年的努力，因为一次错误的决定而毁于一旦。
duonian de nuli, yinwei yici cuowu de jueding er huiyu yidan
Years of effort were ruined by one wrong decision.
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这场大火，将他的毕生心血毁于一旦。
zhei chang da huo, jiang ta de bisheng xinxue huiyu yidan
The fire destroyed his life's work in an instant