The infinitive is the basic, unconjugated form of a verb, sometimes called the name of the verb. In English the infinitive is to + verb: to talk, to eat, to leave, etc. The Spanish infinitive is a single word with one of the following endings: -ar, -er, or -ir.

Perfect Infinitive

The Spanish perfect infinitive indicates an action that occurred before the action of the main verb, but only when the subject of both verbs is the same. The perfect infinitive sounds awkward in English – we usually change it to another tense or reword the sentence completely.