adj.让人不领情的，徒劳无益的，吃力不讨好的

Raising children can be a thankless job, but the rewards are immeasurable.
翻译：养育孩子可能是一项吃力不讨好的工作，但回报是无法估量的。
She works tirelessly for the charity, yet often receives no thanks for her efforts.
翻译：她为慈善机构不知疲倦地工作，然而她的努力常常得不到感谢。
He put in extra hours at work without expecting any recognition or thanks.
翻译：他在工作中加班加点，却并不期待得到任何认可或感谢。
The volunteers' hard work was largely thankless, as their contributions went unnoticed by most people.
翻译：志愿者们的辛勤工作很大程度上是不被感激的，因为他们的贡献大多未被大多数人注意到。
Teaching is a profession where you don't always get the appreciation you deserve, it's often a thankless task.
翻译：教师是一个不总是能得到应得的赞赏的职业，它往往是一项吃力不讨好的任务。
She cooked a delicious meal for the family, but received no thanks or praise.
翻译：她为家人做了一顿美味的饭菜，却没有得到感谢或赞美。
Cleaning up after a party is usually a thankless job, but someone has to do it.
翻译：聚会后打扫卫生通常是一件吃力不讨好的事，但总得有人来做。
He did all the heavy lifting, but never got any credit or thanks for his effort.
翻译：他做了所有繁重的工作，但从没有因他的努力而获得赞誉或感谢。
Despite her dedication, the manager's work was often taken for granted and she rarely received thanks.
翻译：尽管她非常敬业，但经理的工作经常被认为是理所当然的，她很少得到感谢。
They spent countless hours volunteering at the shelter, yet their efforts were often overlooked and unappreciated.
翻译：他们在收容所志愿服务了无数个小时，然而他们的付出常常被忽视和不被感激。