thankless

Cleaning the public beach was a thankless job, but volunteers did it anyway.

清扫公共海滩是一件吃力不讨好的工作，但志愿者们还是做了。

She received a thankless task: reorganizing the old files with no recognition.

她接到了一项无人感激的任务：整理旧文件，却得不到任何认可。

Being a referee is often a thankless role, yet someone has to do it.

当裁判往往是一个吃力不讨好的角色，但总得有人去做。