2.1.2PR0L0G的程序 PROLOG程序一般由一组事实、规则和问题组 成。问题是程序执行的起点,称为程序的目标。 likes(bell, sports) likes(mary, musIc)、蕌 likes(mary, sports).TE likes(jane, smith).蕌 friend(john, X):-likes(X, reading), likes(X, music) friend(john, X): -likes(X, sports), likes(X, music ?-friend (john, Y)