无用的英文：
useless
worthless

参考例句：

It's no use [good]crying over spilt milk.
"覆水难收;木已成舟,哭也无用。"

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

This is far from an idle suggestion.
这决不是无用的提议。

It is useless, yea harmful.
不仅无用而且有害。

Go for nothing; sells for nothing
无用;无价值;徒劳无功

Objectionable or worthless.
令人不快的或无用的

A white elephant possession that is useless and often expensive to maintain
无用的而常指保管昂贵的东西.

These are beings of the great neuter species.
他们全是那一大堆无用人群的组成部分。

Something that is vain, futile, or worthless.
无价值的东西空虚、无用或无价值的东西

One that is burdensome or superfluous.
无用人员，冗员累赘的或多余的人

useless是什么意思：
adj. 无用的；无效的；差劲的，不行的

A well devoid of water is useless.
无水的井没有用途。

Damn this useless typewriter!
这个破打字机真该死!

A car is useless without petrol.
A car is useless without petrol.

After this it was useless to resist.
这一来，再挣扎也没有用啦。

It is the order of nature, and regret is useless.
这是自然的法则，悲叹惋惜是无用的。

worthless是什么意思：
adj. 无价值的，不值钱的，没用处的；卑微的；不中用的，一无是处的

Without wisdom wealth is worthless
如果没有智慧,财富就无价值

Something that is vain, futile, or worthless.
无价值的东西空虚、无用或无价值的东西

Old, worthless, dull and mean
老朽昏庸

Something insubstantial,worthless,or fleeting.
无实质之物没有实质、没有价值或飞逝的东西

Something loathsome,despicable,or worthless.
污垢，渣滓，可鄙者令人厌恶、可鄙或无用的事物