维持熟悉表情陌生关系不变
[wéi chí shú xī biăo qíng mò shēng guān xì bù biàn]
It describes a situation in which people try to stay friends but not lovers, pretending things are as usual and friendly as before after certain change, e.g., the breakdown of romance. They keep the familiar smile but now share only superficial interaction and a relationship no more than acquaintance. A typical phrase one may choose who had experienced love failure or breakup but still want to stay connected in some degree.