waste breath
白费口舌
口语·白费口舌
英文释义
to expend energy or effort on something that is futile or ineffective
例句
Trying to convince him is a waste breath; he won't listen.
典故来源
字面意为浪费呼吸，比喻说话毫无效果，源于日常对话中对徒劳劝说的形象描述。