student(mark).
student(steve).
student(helen).
student(sylvia).
student(pauline).
student(frank).

female(helen).
female(sylvia).
female(pauline).

male(mark).
male(steve).
male(frank).

clever(helen).
clever(steve).
clever(pauline).

works_hard(helen).
works_hard(mark).
works_hard(frank).