Questions about the Present Perfect
Q: Why is it he hablado and NOT he hablar?
R: The present perfect is formed with the present of haber, followed by a past participle (not the infinitive).
Q: Why is it he roto and NOT he rompido?
R: The verb romper has an irregular past participle (roto).
Q: Why is it La mujer que he visto and NOT La mujer que he vista?
R: One does not make agreement with a subject when the auxiliary verb is haber.