List the irregular verbs that change to an i-stem in the past tense
Querer (quise), Venir (vine), Hacer (hice),
List the irregular verbs that change to a u-stem in the past tense
Estar (estuve), Andar (anduve), Tener (tuve)
List the irregular verbs that change to a J-stem in the past tense
Decir (dije), Traer (Traje), Conducir (Conduje)
List the irregular verbs that change to a Y-stem in the past tense
Caer (cayeron), oír (oyó), leer (leyó), creer (creó)