Mainly responsible for picking up balls for tennis players, delivering balls, changing towels, etc., but everything has technical content. For example, when rolling a ball on the field, caddies must not roll the ball diagonally between each other, because players walking in the middle of the field will be injured if they step on the ball. So even if the two caddies are standing in a diagonal line, they must find a third person in the middle to transition into a straight line. Caddies stand closest to the masters on the court during the game. No slight expression can escape their sight. Many spectators will envy their "privilege", but caddies are not allowed to ask for autographs from players. The work is also very tiring, and sometimes you will encounter difficult bosses. You are not allowed to make a mistake during the game. If you make a small mistake and the referee sees it, you will have to pack up and go home.