There is actually another explanation: 1. First judge the total score of 5 games. Because C was the referee three times, A and B played three games. The title said that A and B appeared four times each, so A and C got 1 field, and B and C got 1 field, making a total of five games.

2. Since the probability of A and B is the same, A can be used to represent A and B, and B can be used to represent C. Asking the loser in the second game is actually asking the referee in the third game. I assume that A (A or B) is used to represent the referee of the third game, that is, the loser of the second game is A (A or B), then the third game can be expressed as A B A, and you can infer the situation of other games accordingly. Anyway, according to this situation, it is absolutely impossible for C to be a referee three times.

To sum up, the referee in the third game is B, that is, C, that is, the loser in the second game is C.

I hope it helps you!