Kilo Lingo
Part of Chapter 33

CEFR B1-B2

Test yourself (14 questions)

The Infinitive as a Noun and After Prepositions

There is one mistake English learners of Spanish make more than any other, and it is not a matter of vocabulary or accents. It is the -ing form. In English, when an action behaves like a noun - smoking is bad, before leaving, without thinking, on arriving - we end it in -ing. So learners go looking for a Spanish -ing to match, and reach for the gerund: fumando, saliendo, pensando. It is wrong nearly every time.

Where English uses the noun-like -ing, Spanish uses the plain infinitive - the dictionary form ending in -ar, -er or -ir. The infinitive is not just a verb waiting to be conjugated. It is Spanish's verbal noun: it names the action, it works as a subject, and it slots in after every preposition. Learn that one fact and a whole category of errors disappears.

The infinitive as a noun

An infinitive can be the subject of a sentence - the thing the sentence is about - exactly where English would use the -ing form.

  • Fumar es malo. (Smoking is bad.)
  • Nadar es mi deporte favorito. (Swimming is my favourite sport.)
  • Viajar abre la mente. (Travelling opens the mind.)
  • Aprender idiomas es útil. (Learning languages is useful.)

Notice there is no -ando or -iendo anywhere. The subject is the bare infinitive, and the verb that follows it is singular, because a nominalised infinitive counts as a masculine singular noun.

You can also put the article el in front, which makes the action sound a touch more abstract or weighty - common in general truths and headlines.

  • El comer bien es importante. (Eating well is important.)
  • El fumar perjudica la salud. (Smoking harms your health.)
  • El viajar cuesta dinero. (Travelling costs money.)

The el is optional. Comer bien es importante is just as correct and slightly more everyday. But when you do use an article, it is always el - masculine, singular, whatever the verb. You would never write la comer or try to make it plural.

The infinitive after prepositions

This is the big one. After every preposition, Spanish uses the infinitive where English uses the -ing form. There are no exceptions to hunt for.

PrepositionSpanishEnglish
antes deantes de salirbefore leaving
después dedespués de comerafter eating
sinsin pensarwithout thinking
parapara ganarin order to win
en vez deen vez de trabajarinstead of working
además deademás de serbesides being
porpor llegar tardefor arriving late
hastahasta terminaruntil finishing

Some of these in full sentences:

  • Antes de salir, cierra la puerta. (Before leaving, close the door.)
  • Después de comer, dormimos la siesta. (After eating, we have a nap.)
  • Se fue sin decir nada. (He left without saying anything.)
  • Estudio para aprobar el examen. (I study in order to pass the exam.)
  • En vez de trabajar, se quedó en la cama. (Instead of working, he stayed in bed.)
  • Además de ser guapo, es simpático. (Besides being handsome, he is nice.)

Every single one uses the infinitive. Say antes de saliendo or sin pensando and you have marked yourself as a beginner in three words. The rule is watertight: preposition + infinitive, never preposition + gerund.

al + infinitive: "on / upon doing" or "when"

There is one preposition-plus-infinitive combination worth its own section, because it does something English handles with a whole clause. Al (the contraction of a + el) followed by an infinitive means "on" or "upon" doing something, or simply "when" it happens. It ties one action to the exact moment of another.

  • Al llegar a casa, me quité los zapatos. (On arriving home, I took off my shoes.)
  • Al verla, sonrió. (On seeing her, he smiled.)
  • Al oír la noticia, se puso a llorar. (On hearing the news, she burst into tears.)
  • Al abrir la puerta, noté el frío. (When I opened the door, I felt the cold.)

The clever part is that al + infinitive carries no tense of its own - it borrows its timing from the main verb. Al salir can mean "when I leave", "when I left" or "when I will leave", entirely depending on the surrounding sentence. It is far more compact than a full cuando clause, and much more natural in speech: al terminar, te llamo (when I finish, I'll call you) beats the wordier cuando termine, te llamo for a quick, simultaneous action.

After verbs, too

The infinitive is also the form that follows another conjugated verb directly - quiero comer (I want to eat), puedo ir (I can go). And crucially, after gustar and its relatives, the thing you like is expressed as an infinitive, not a gerund.

  • Me gusta nadar. (I like swimming.) Never me gusta nadando.
  • Nos encanta viajar. (We love travelling.)
  • Le molesta esperar. (Waiting annoys him.)

English "I like swimming" fools learners into me gusta nadando constantly. It is me gusta nadar: the infinitive naming the activity you enjoy.

Where the gerund actually belongs

To keep the line clear: the Spanish gerund (hablando, comiendo, viviendo) has real jobs, just not these ones. It describes an action in progress, usually with estar - estoy comiendo (I am eating) - or works like an adverb - salió corriendo (he ran out). Those are separate topics. The moment an action needs to behave like a noun - as a subject, or after a preposition - the gerund steps aside and the infinitive takes over.

Common mistakes English speakers make

Translating the noun-like -ing with a gerund. "Smoking is bad" becomes fumando es malo in the learner's head; it is fumar es malo. Any -ing that works as a subject is an infinitive in Spanish.

Using the gerund after a preposition. Antes de saliendo, sin pensando, después de comiendo are all wrong. After a preposition the form is invariably the infinitive: antes de salir, sin pensar, después de comer.

Saying me gusta nadando. After gustar, encantar and friends, the activity is an infinitive: me gusta nadar, le encanta cantar. The gerund never appears here.

Forgetting that al means "on/when". Learners read al llegar as "to the arrive" and freeze. It is a fixed construction: al + infinitive = "on doing / when doing", with its tense borrowed from the main verb.

Get these two uses right - the infinitive as a noun, and the infinitive after prepositions - and you will already sound markedly less like a translated Englishman. When in doubt and an -ing is tugging at you, reach for the infinitive first.

See also

Practise: test yourself

Fill in the blank

0/8

Fill the gap with the correct infinitive of the verb in brackets. Remember: after a preposition, and as the noun/subject of a clause, Spanish uses the infinitive, never the -ing form.

  1. es malo para la salud. (fumar) (smoking = the subject)

  2. Antes de , apaga la luz. (salir) (before leaving)

  3. Se fue sin nada. (decir) (without saying)

  4. Estudio mucho para el examen. (aprobar) (in order to pass)

  5. Al a casa, me quité los zapatos. (llegar) (on arriving)

  6. En vez de , deberías descansar. (trabajar) (instead of working)

  7. Además de guapo, es simpático. (ser) (besides being)

  8. Después de , fuimos al cine. (cenar) (after having dinner)

Pick the right one

0/6

Choose the correct form. Spanish uses the infinitive as a noun and after prepositions where English uses the -ing form.

  1. Me gusta por la playa.

  2. idiomas abre puertas.

  3. Lo hizo sin .

  4. Al la noticia, se puso a llorar.

  5. El bien es importante.

  6. Insisto en la verdad.

Frequently asked questions

Why does Spanish use the infinitive where English uses the -ing form?
Because the infinitive is the verbal noun in Spanish, doing the job English hands to the gerund. When an action works as a noun - as the subject of a sentence, or as the thing that follows a preposition - Spanish reaches for the infinitive, not the -ing form. So 'smoking is bad' is fumar es malo, and 'before leaving' is antes de salir. The Spanish gerund (fumando, saliendo) exists, but it is reserved for other jobs: describing an action in progress with estar, or acting like an adverb. After a preposition or as a subject, it is simply wrong. The safe rule: translate an English noun-like -ing with the infinitive.
What does al + infinitive mean in Spanish?
Al + infinitive means 'on' or 'upon' doing something, or 'when' something happens - a neat way to pin one action to the moment of another. Al llegar a casa is 'on arriving home' or 'when I got home'; al verla, sonrió is 'on seeing her, he smiled'. It is formed from the contraction al (a + el) plus the plain infinitive, and it takes its timing from the main verb, so al salir can mean 'when I leave', 'when I left' or 'when I will leave' depending on context. It is compact, common and very natural - far more idiomatic than a full cuando clause for a quick simultaneous action.
Can you put the article el in front of an infinitive in Spanish?
Yes. Adding el turns the infinitive into a full-blown noun, often to make a general statement sound weightier or more abstract: el comer bien es importante (eating well is important), el fumar perjudica la salud (smoking harms your health). The bare infinitive works too - comer bien es importante is perfectly correct - so the el is optional and slightly more formal or emphatic. Note the article is always el, masculine singular, regardless of the verb, because a nominalised infinitive is treated as a masculine noun. You would never use la or make it plural.
What is the difference between the infinitive and the gerund in Spanish?
They divide the labour that English piles onto the -ing form. The infinitive (hablar, comer, vivir) is the verbal noun: it names the action and works as a subject or after a preposition - hablar es fácil (speaking is easy), sin comer (without eating). The gerund (hablando, comiendo, viviendo) is the verbal adverb: it describes an action in progress, mostly with estar (estoy comiendo, I am eating), or modifies another verb (salió corriendo, he ran out). The classic error is using the gerund where the infinitive belongs. 'I like swimming' is me gusta nadar, never 'me gusta nadando'.