正当理由

The rights of citizens must not be abridged without proper cause.

有正当理由, 不能擅自剥夺公民的权利。

You HAs no grounds to agoing away of the contract.

你们么有正当理由背弃合同。

I think it is a totally unwarranted waste of public money.

我认为这是毫正当理由地浪费公款。