Sister Moon, come down and sing in turn to enhance the effect of the song. In the process of singing, the method of rotating singing is used to create the atmosphere of the song and enhance the performance effect. Rotation singing is an important part of chorus, which is conducive to the singer's singing enthusiasm and creative potential, so that he can fully appreciate the harmonious effect of different voices intertwined. The same melody is sung by two or more voices, but the chorus does not start at the same time, but is separated by one beat, several beats or one bar, forming a continuous imitation effect, which is called round singing.