used to refer to a point at which you start achieving less than the value of the time or money you put into something选举；选出；推举
Our efforts were producing diminishing returns.我们不断投入，收益却在递减。
In general, the more exercise you take, the greater the health benefit; but beyond a certain level you get diminishing returns.一般来说，你锻炼得越多，对健康的好处就越大；但是超过一定的水平，你得到的回报就会减少。