ineffective
单词辨析：
指努力、希望、搜寻等未能获得想要的结果的。
He underwent a knee operation in the vain hope of getting into the team.
他做了膝盖手术，徒劳地指望能进入该队。
She raised her head in a vain attempt to hold back the tears.
她仰起头，却无法忍住眼泪。
指行动、计划等没有成功的。
an abortive takeover bid by the larger firm
由较大公司提出的夭折了的并购
There is no record of the abortive military coup.
没有关于那次未遂的军事政变的记录。
尤指付出很多努力却无成效的。
So far, their research has been fruitless.
到目前为止，他们的研究工作毫无结果。
The fruitless attempt to settle the dispute disappointed him.
试图解决争端的努力白费了，这让他很失望。
侧重指人或事物未能发挥应有之作用的。
The army has proved ineffective in protecting the local civilians.
军队没有起到保护当地平民的作用。
This special stain remover was almost ineffective in removing the soup stain.
这种特效去污剂基本去不掉汤渍。
The policy proved ineffective in dealing with the problem.
事实证明该政策未能解决问题。
相关例句：
If they prove ineffective they should be demoted or asked to retire.
如果事实证明他们已无力胜任，应该将他们降级或让他们退休。
If individual provisions of this Contract are or become ineffective, this shall not affect other provisions.
本合同的个别条款无效或失效，将不影响其他条款。
Ask a physician, I know the most costly and dramatic measures may be ineffective and painful.
作为一名医生，我深知最昂贵和最激进的手段也可能是无效的和痛苦的。
After all, the expenditures can often seem wasteful and ineffective.
毕竟，各项花费常常看起来是浪费和低效的。
But if he stays in power, analysts believe he will be weak and ineffective.
但是如果他掌权，分析家认为他将是微弱和无效的。
Furthermore, they claim that any such interference is completely ineffective.
此外，他们还声称任何这样的干预都是完全无效的。