s --> np(subjective,Person),vp(Person). np(Case,1) --> pronoun(Case,1). np(Case,3) --> pronoun(Case,3); (article,noun). vp(Person) --> verb(Person); verb(Person),(adverb; adjective; pp; np(objective,3)). pp --> preposition,article,noun. % load knowledgebase :- consult('knowledgebase_2.pl').