九仞一篑 Nine ren [a traditional Chinese unit of measure, about 3.3 meters], one basket of earth
Explanation
比喻事情做到最后关头功亏一篑，最终失败。这个成语出自《尚书·旅獒》:
It's a metaphor for something failing at the last minute, ultimately ending in failure. This idiom comes from the book "Shangshu·Lǚ áo":
Origin Story
很久以前，有一个勤劳的农民，为了种好地，他每天都辛勤地劳作，经过好几年的努力，终于将自己的田地整理的非常适合耕作，眼看着就要收获了，然而就在收获的最后一天，他发现自己的田地因为长时间无人照料，被野兔糟蹋得不成样子，农民眼看着自己的努力付诸东流，不禁心生悲凉。这个故事告诉我们，凡事都要坚持到底，不要半途而废，否则就会功亏一篑，一事无成。
A long time ago, there was a hardworking farmer who worked diligently every day to cultivate his land. After years of effort, he finally made his land suitable for farming. He was about to harvest, but on the last day of the harvest, he found that his land had been ruined by wild rabbits because it had been unattended for a long time. The farmer watched his efforts go to waste and couldn't help but feel sad. This story tells us that we must persevere in everything we do and never give up halfway, otherwise we will fail at the last moment and achieve nothing.
Usage
形容事情做到最后关头功亏一篑，最终失败。
It describes something failing at the last minute, ultimately ending in failure.
Examples
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这次的项目眼看就要成功了，却因为最后一点小问题功亏一篑，真是可惜！
cì cì de xiàng mù yǎn kàn jiù yào chéng gōng le, què yīn wéi zuì hòu yī diǎn xiǎo wèn tí gōng kuī yī kuì, zhēn shì kě xī!
The project was about to be successful, but it failed at the last minute because of a small problem. What a pity!
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他们已经付出了那么多努力，就差最后一步了，千万不要功亏一篑。
tā men yǐ jīng fù chū le nà me duō nǔ lì, jiù chà zuì hòu yī bù le, qiān wàn bù yào gōng kuī yī kuì
They have put in so much effort, just one last step away from success. Don't fail at the last moment!