Two time and four time. Carols can be roughly divided into three categories: the first type of carol has a broad melody, a slow speed, and a solemn and majestic spirit. The second type of carol has a march style, and mostly uses two beats and four beats. Because the melody is resolute and heroic, and the momentum is majestic, so it adopts two beats and four beats. The third type of ode has the characteristics of a lyrical song, with a broad and singing atmosphere, expressing deep affection for the people and things being sung. Odes refer to songs of praise and blessing. See Jing of the Tang Dynasty and Song Dynasty's "Thanks for the Banquet": "The sound of joy is echoed by billions of trillions, and the feeling is so great that it takes the shape of an ode." In the ancient Greek period, odes were poems written for major ceremonies, using gorgeous chorus forms, Accompanied by dancing and musical instruments.