Prepare more than a dozen questions in the first round of the first day, and let each class draw one in order. Then give a few minutes to prepare, and then go to another classroom to debate with teacher 4, and choose the top four according to the teacher's score. In the second round, the fourth and third place compete for the third place, which requires a real debate between the two sides, one positive and one negative, and the judges score.
This is all my own idea! Must be original. I wonder if I can help you. Wish you success!