临渴掘井 Dig a well when thirsty
Explanation
比喻做事没有预先准备，等到需要的时候才想办法，往往为时已晚。
It describes doing something only at the moment when you urgently need it, which often means that it is too late.
Origin Story
春秋时期，鲁昭公被赶出鲁国，逃到齐国。齐景公问他为什么失去王位，他说自己没有任用贤才，只信任阿谀奉承的人。齐景公问晏婴鲁昭公能否东山再起，晏婴说："临渴掘井，怎么能成功呢？"
During the Spring and Autumn period, Duke Zhao of Lu was expelled from his state and fled to Qi. Duke Jing of Qi asked him why he had lost his throne, and he replied that he had not employed able men but only those who flattered him. Duke Jing then asked Yan Ying whether Duke Zhao could stage a comeback, and Yan Ying replied, "How could one who digs a well only when thirsty ever succeed?"
Usage
形容做事没有准备，临时抱佛脚。
It describes someone who does something at the last minute without any preparation.
Examples
-
他临阵磨枪，准备不足，考试自然考砸了。
tā lín zhèn mó qiāng, zhǔnbèi bù zú, kǎoshì zìrán kǎo zá le.
He started cramming at the last minute, so he failed the exam naturally.
-
这次的项目准备时间仓促，有点临渴掘井的感觉。
zhè cì de xiàngmù zhǔnbèi shíjiān cāngcù, yǒudiǎn lín kě jué jǐng de gǎnjué
The project preparation time for this time was rushed, and it felt a little like digging a well when thirsty..