Today we're going to get a double attack: how to use the dynamic duo of auxiliary verbs to create the Modal perfect tense, and how to function with three or more verbs in a sentence.
In English, our Modal perfect is "should have" in relation to what would have been optimal for someone to do. In a way, it's a bit similar to conditional perfect. To create a Modal perfect verb combination, here's how it goes:
Conjugation of Deber + Haber + De + Infinitive verb
If you have more than one infinitive verb, it might be better just to use a comma or start a new sentence. We went over how to conjugate deber in the last chapter, but I think it's worth going over again so that we don't forget:
Yo: Debo
Tú: Debes
Él, ella, ud: Debe
Nosotros: Debemos
Vosotros: Debéis
Ellos, ellas, uds: Deben
Debo haber de comer ayer. ｜I should have eaten yesterday.
Debes haber de limpiar tus ropas. ｜You should have cleaned your clothes.
Ella debe haber de bailar con él. ｜She should have danced with him.
Debo haber de comprar esa piscina. ｜I should have bought that pool.
Debemos haber de reconciliar antes. ｜We should have reconciled before.
Deben haber cocinar esa cena. ｜They should have cooked that dinner.