How should the referee deal with the athletes who violate the rules ?
2. Before serving, if the receiver proposes to change the ball and the server disagrees, what should the referee do?
3. What is elimination? What are its advantages and disadvantages ?
4. Athletes a and B of Guangdong team and athletes X and y of Jiangsu team will compete in men’s doubles in team competition. How to announce at the beginning of the competition?