sufficient(hong_kong, time).
sufficient(hong_kong, budget).
insufficient(new_york, time).
insufficient(new_york,budget).
sufficient(john, time).
sufficient(john, budget).
kind(john, food_and_shopping).
preference(john, local_flavor).
insufficient(lily, time).
insufficient(lily, budget).
kind(lily, food_and_shopping).
preference(lily, local_flavor).
%%%%%%%%%%%%% Rules
travel_new_york(x) :-
kind(x,food_and_shopping),
preference(x,local_flavor),
insufficient(x,time);
insufficient(x,budget).
travel_hong_kong(x) :-
kind(x,food_and_shopping),
preference(x,local_flavor),
sufficient(x,time),
sufficient(x,budget).
规则不能执行，总是false

x是变量吧，prolog里变量要首字母大写，X或What这样