无效的英文：
not valid
ineffective
in vain

A futile attempt
无效的尝试

To annul or invalidate.
取消，使无效

Invalid Destination
目的地无效

The entry is invalid.
项目无效。

Invalid Domain
无效的域

To defeat;invalidate.
打败;使无效

Invalid filename.
文件名无效。

The handle is invalid.
句柄无效。

Incompetent evidence
法律上无效的证据

To make ineffectual or invalid;nullify.
使无效果或无用;使无效

He is validating his findings.
他正在验证他的发现。

The validity of the hypothesis can be tested.
这种假说的可靠性是经得起考验的。

There is no question about the validity of the enterprise.
对这企业的合法性没有任何怀疑。

One that is disappointingly ineffective or unsuccessful.
无用的人或物的令人失望的无用的或不成功的人或物

Economic reform will continue to be painful and ineffective.
经济改革仍将举步维艰，毫无成效。

The air-conditioner was ineffective in such a crowded room.
在挤那么多人的房间里空气调节器不起作用了。

It was a vain effort.
这种努力是徒劳无益的。

This is a vain and fleeting thing.
这是一种空虚的、转瞬即逝的东西。

She is vain and extravagant.
她既爱虚荣又奢侈。