得不偿失 a losing proposition
Explanation
指付出的代价超过了获得的利益，最终是亏本的。
It refers to the cost paid exceeds the benefits obtained, and ultimately it is a loss-making business.
Origin Story
三国时期，吴国大将鲁肃奉命攻打荆州。当时荆州军民众多，城池坚固，吴军兵力不足，鲁肃深知强攻荆州得不偿失，于是他决定采取策略，先稳固吴国的地盘，积蓄力量，再图发展，最终避免了一场损失惨重的战争。
During the Three Kingdoms period, Wu general Lu Su was ordered to attack Jingzhou. At that time, Jingzhou had a large population and strong fortifications, and Wu's forces were insufficient. Lu Su knew that a strong attack on Jingzhou would be a losing proposition, so he decided to adopt a strategy of first consolidating Wu's territory, accumulating strength, and then planning for further development, ultimately avoiding a costly war.
Usage
用于形容某种行为或决策的收益低于损失，得不偿失。
Used to describe an action or decision where the benefits are less than the losses, resulting in a net loss.
Examples
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这次投资虽然赚了一些钱，但付出的代价太大了，真是得不偿失。
zhe ci touzi suiran zhuan le yixie qian, dan fuchu de daijia tai da le, zhen shi de bu chang shi.
This investment although made some money, but the cost is too high, it is really a losing proposition.
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为了追求眼前的小利，他放弃了长远发展的机会，最终得不偿失。
weile zhuiqiu yanqian de xiao li, ta fangqile changyuan fazhan de jihui, zhongjiu de bu chang shi
In order to pursue immediate benefits, he gave up the opportunity for long-term development, and ultimately lost out.