一了百当 once and for all
Explanation
指事情办得妥当、彻底。
means that something is done properly and thoroughly.
Origin Story
话说唐朝时期，有一位名叫李白的诗人，他一生豪迈不羁，挥笔泼墨，写下了许多千古流传的佳作。但是，李白也并非完美无缺，他的生活常常是放荡不羁，缺乏一定的计划性和条理性。有一天，李白突然心血来潮，决定要写一篇千古名篇，于是他关起门来，潜心创作。他夜以继日地写作，废寝忘食，直到把这篇作品写完才罢休。李白写完这篇文章后，欣喜若狂，他觉得自己的这篇作品，一定会名垂青史，成为后世人们争相传颂的经典。他把自己的作品拿给朋友们看，朋友们纷纷赞叹他的才华横溢，认为这篇作品确实是一篇不可多得的佳作。李白看到朋友们的评价如此之高，更加得意洋洋。从此以后，李白更加努力地写作，希望能够写出更多更好的作品，让自己的名字永远地流传下去。
In the Tang Dynasty, there was a poet named Li Bai, known for his unrestrained and flamboyant works. One day, he decided to write a masterpiece, so he locked himself in his room for days, working tirelessly and forgetting to eat and sleep. After completing the work, he was overjoyed. He showed it to his friends, who praised his talent. Li Bai was proud of his achievement, which brought him the success he had hoped for. The work was a great success and remains famous to this day.
Usage
形容事情办得彻底，没有后顾之忧。
describes something that was done thoroughly and completely, without any lingering concerns.
Examples
-
他做事一向一了百当，从不拖泥带水。
tā zuòshì yīxiàng yīliǎobǎidàng, cóng bù tuōnídàishuǐ
He always does things thoroughly and efficiently.
-
这次的难题，被他一了百当地解决了。
zhè cì de nántí, bèi tā yīliǎobǎidàng de jiějué le
He solved this difficult problem all at once