off and on
断断续续地，有时候
口语·描述不规律或间歇性行为
英文释义
occurring intermittently or not consistently
例句
We've been dating off and on for two years, but never seriously.
典故来源
源自19世纪，指事物像开关一样时而开启时而关闭，形容不连续的状态。