Definition
To behave very well, especially used to describe a child.
（兒童）很乖，很聽話
He has been as good as gold today since I told him I’d take him to the park if he behaved well.
自從我告訴他如果表現好就帶他去公園，他今天一直都非常乖巧。
The children were as good as gold throughout the entire trip, with no complaints.
孩子們在整個旅程中都表現得非常乖巧，沒有任何抱怨。
Despite usually being mischievous, he was as good as gold tonight.
儘管平時很調皮，他今晚卻非常乖巧。