An infinitive (el infinitivo) is the most basic verb form in all languages. In English, it is always preceded by "to," as in "to run," "to love," and "to travel." In Spanish, infinitives consist of only one word and are separated into three different conjugations according to their endings: -ar, -er, or -ir. These endings are attached to the root of a verb to form the whole infinitive (hablar, correr, compartir). Verbs in the infinitive form indicate what the action is but nothing about who is doing the action at what point in time.
Uses of the Infinitive
1. As a Base for Conjugations
All of the indicative and some of the subjunctive start with the infinitive. As you will see in many verb references, the first step to conjugating involves "the stem of the infinitive." To find the stem, simply take off the infinitive ending (-ar, -er, or -ir).
- amar (to love) -> amo, amas, ama, amamos, amáis, aman
- comer (to eat) -> como, comes, come, comemos, coméis, comen
- abrir (to open) -> abro, abres, abre, abrimos, abrís, abren
In Spanish, when a verb functions as a noun, the infinitive is used. In English, the gerund (verbs that end in -ing) is used in these instances, but not in Spanish where the gerund is only used in expressing continuous actions such as the present progressive.
- Hablar español es divertido. (Speaking Spanish is fun.)
- Está prohibido sacar fotos. (Taking pictures is prohibited.)
3. After a Conjugated Verb
Infinitives can be used many different ways with or without prepositions to express the idea of "to do" something.
- Vamos a bailar. (We are going to dance.)
- Tienes que sacar la basura. (You have to take out the trash.)
- Quiero salir para la fiesta. (I want to leave for the party.)
- Me gusta dibujar. (I like to draw.)
1) Write the stem for each infinitive given.
Example: bailar -> bail