likes(bell, sports).HE likes(mary, music), Ax u likes(mary, sports).HE likes(jane, smith) friend (john, X): -likes(X, reading), likes(X, music friend(john, X): -likes(X, sports), likes(X, music ?-friend (john, Y) 则求解目标为 friend(john, Y 新目标蕌 likes(X, reading), likes(X, music).ti