Before you read this comment on the preterit, back up to the previous ones. Keep in mind that in general Spanish does not place three vowels together unless one is accented. So in preterit cases like Leer, Creer, and Oír, once you drop the ER/IR and add IO, there will be three unstressed vowels side by side. Change the I to a Yin the third persons. The 3rd person preterit for these verbs is leyó, creyó and oyó. In the exercise that follows, fill the gaps with the missing conjugations.