adj.没有成果的，无成效的，徒然的

The search for a cure was fruitless; no effective treatment was found.
治愈的方法毫无结果；没有找到有效的疗法。
His efforts to learn a new language were fruitless; he never mastered it.
他学习新语言的努力徒劳无功，始终无法精通。
Her attempts at starting a business venture proved fruitless, as it failed after six months.
她创业尝试最终无果，六个月后就倒闭了。
The negotiations between the two countries were fruitless; they couldn't agree on any terms.
双方国家的谈判毫无进展，未能达成任何协议。
I spent hours searching for my keys, but they turned out to be right in my pocket - what a fruitless effort! 我找了几个小时的钥匙，结果发现它们就在我口袋里，真是白费工夫！
His study of ancient languages was fruitless, as there's little written material left from that era.
他对古代语言的研究毫无收获，因为那个时代的文献留存极少。
The experiment to grow new crop varieties was fruitless, as none of them showed promising results.
种植新型作物品种的实验没有成效，没有一种显示出有希望的结果。
She tried every diet fad, but her weight loss journey remained fruitless.
她试过各种减肥法，但减肥之旅仍然没有成效。
The detective's investigation into the crime scene was fruitless; no clues led to the culprit.
警探对犯罪现场的调查毫无所获，没有线索指向嫌疑人。
After countless revisions, her manuscript was rejected by every publisher – her writing career seemed fruitless.
经过无数次修改，她的手稿被所有出版社拒绝，她的写作生涯似乎毫无起色。