Panjin played two sets of matches, questioned Xiao Ming and tried several times to calculate.
Xiao Wang played two sets. Because A played four sets, A, B, C and Xiao Wang all played, D played 1 set, which means D hasn't played with B, C and Xiao Wang, and B played three sets, so B, C and Xiao Wang played, while C played two sets with A and B, which means C hasn't played yet.