idiom · a metaphorical description of a flourishing, thriving, and joyous atmosphere

改革开放以来，祖国各地呈现出一派莺歌燕舞的繁荣景象。

idiom · a lively and beautiful scene of spring characterized by birds singing and dancing

在这莺歌燕舞的季节里，公园里的游人络绎不绝。