Introduction
Many English-speaking learners stumble over when to use de before a Spanish infinitive. This article clears up common mistakes, explains the grammar rules step by step, and gives plenty of real examples so you can use de with confidence.
- Why prepositions matter with infinitives
- Common verbs and expressions that require de + infinitive
- Common mistakes and how to avoid them
- How to identify whether a verb needs de
- Common verbs that do NOT take de before infinitives
- Examples showing meaning changes with de
- Useful collocations and examples
- Regional variations and usage notes
- Quick reference list
- Practical tips for study
- Conclusion
Why prepositions matter with infinitives
In Spanish, prepositions are often required where English would use nothing or a different word. One of the most frequent cases is using de before an infinitive verb, for example in verbs that require a preposition or in certain constructions. Choosing the wrong preposition—or leaving it out—can change the meaning or make a sentence ungrammatical.
English vs Spanish: a quick contrast
In English you can say I want to go, but Spanish uses querer + infinitive: quiero ir. No preposition is needed after querer. However, other verbs and expressions that look similar in meaning do require de. Recognizing which verbs take de is essential.
Common verbs and expressions that require de + infinitive
Below are categories and lists of verbs or expressions that commonly require de before an infinitive. Learn these patterns and watch out for false friends—verbs that look like English equivalents but behave differently.
Verbs of opinion, doubt, and certainty
Some verbs expressing opinions, emotions, or doubts require de when followed by an action in infinitive form. Examples:
alegrarse de + infinitive: Me alegro de verte.
dudar de + infinitive: Dudo de poder venir.
arrepentirse de + infinitive: Me arrepiento de decirlo.
Notice these verbs often connect an emotional state or attitude with the action, and the preposition de links them to the infinitive.
Verbs that express obligation, responsibility, or lack thereof
Some verbs require de when describing someone being obliged or not obliged to do something.
encargarse de + infinitive: Me encargo de organizar la fiesta.
dejar de + infinitive: Dejé de fumar.
olvidarse de + infinitive: Se olvidó de llamar.
Note that dejar alone can mean let or allow (dejar + infinitive without de) and dejar de means stop doing something. The presence or absence of de changes meaning.
Verbs of perception and cognition that use de
Certain verbs that in English might be rendered similarly to verbs that take a bare infinitive in Spanish actually require de when they involve thinking about or perceiving an action as an abstract idea.
acordarse de + infinitive: Me acuerdo de comprar pan.
imaginarse de + infinitive: Me imagino de terminar pronto. (More common: imaginarse + que … but this shows usage.)
Be careful: verbs like saber and creer usually take a clause or direct infinitive in specific contexts and do not use de in the same way.
Common mistakes and how to avoid them
Here are frequent errors learners make about de before infinitives, with clear corrections and short explanations.
1. Omitting de when the verb requires it
Wrong: Me alegro verte.
Correct: Me alegro de verte.
Why: alegrarse requires de to connect the emotion to the action.
2. Adding de unnecessarily after verbs that do not take it
Wrong: Quiero de estudiar más.
Correct: Quiero estudiar más.
Why: querer is followed directly by an infinitive without a preposition.
3. Confusing dejar and dejar de
Wrong: Deja de entrar. (If you mean let him enter.)
Correct: Deja entrar. = allow him to enter.
Correct: Deja de entrar. = stop entering.
Why: dejar + infinitive means permit; dejar de + infinitive means cease.
4. Using de instead of que with subordinate clauses
Wrong: Creo de que viene.
Correct: Creo que viene.
Why: creer takes que to introduce a subordinate clause, not de.
How to identify whether a verb needs de
There is no single trick, but several practical strategies help you decide when to use de.
Learn verbs in chunks
When studying a new verb, learn it with its required preposition if it has one. For example memorise alegrarse de, olvidarse de, encargarse de. This prevents errors when you form sentences later.
Ask what the verb expresses
If the verb expresses emotion, doubt, or responsibility, suspect de. If it expresses desire, ability, or preference, it may take a direct infinitive without preposition (for example querer, poder, preferir).
Look for patterns with reflexive verbs
Many reflexive verbs that relate to memory, emotion, or duties commonly take de. Examples include arrepentirse de, alegrarse de, olvidarse de, preocuparse de. Keep a list of frequent reflexive patterns.
Check whether the English translation uses of or about
Often verbs that in English use of, about, or from are translated with de. For example be afraid of translates to tener miedo de. This connection can be a cue, but always verify with examples.
Common verbs that do NOT take de before infinitives
It helps to contrast verbs that look similar but behave differently. Below are verbs that typically go directly into an infinitive without de.
querer + infinitive: Quiero aprender español.
poder + infinitive: Puedo ayudarte.
deber + infinitive: Debes estudiar más.
necesitar + infinitive: Necesito descansar.
preferir + infinitive: Prefiero comer fuera.
Memorize these core action verbs and avoid inserting de after them.
Examples showing meaning changes with de
Small prepositions can make big meaning differences. Compare these pairs to see how de changes sense.
1) olvidar + infinitive vs olvidarse de + infinitive
Olvidar la llave en casa. = To forget the key at home. (transitive)
Olvidarse de llamar. = To forget to call. (intransitive reflexive)
2) empezar a + infinitive vs empezar por + infinitive vs empezar de (rare)
Empezó a estudiar a las ocho. = He started studying at eight.
Empezó por explicar las reglas. = He began by explaining the rules.
3) deber de + infinitive vs deber + infinitive
Debes estudiar. = You should study / you must study.
Debe de ser tarde. = It is probably late. (deber de + infinitive expresses probability in some contexts)
Useful collocations and examples
Here are practical sentences illustrating common uses of de before infinitives. Read them out loud and notice how the preposition connects ideas.
Tengo miedo de volar.
Se olvidó de traer el pasaporte.
Nos encargamos de limpiar la casa.
Me arrepiento de haberlo dicho.
Dudo de poder terminar hoy.
Traté de llamar varias veces. (Note: tratar de + infinitive = try to)
Many useful verbs combine naturally with de, especially when the speaker expresses emotion, doubt, or a relationship to an action rather than a direct action.
Regional variations and usage notes
Some uses involving de vary by region or register. For example, the use of deber de + infinitive to indicate probability is becoming less common in some areas, with deber + infinitive or quizás + subjunctive used instead to express conjecture. Also, colloquial speech sometimes shortens or omits prepositions, but in formal and written Spanish you should follow standard patterns.
In some Latin American dialects, pronoun placement and reflexive constructions can affect how natural a phrase sounds. Focus on mastering the standard grammatical patterns first, then listen to native speakers from regions that interest you.
Quick reference list
Verbs commonly followed by de: alegrarse de, acordarse de, olvidarse de, encargarse de, arrepentirse de, dudar de, tratar de, sentirse capaz de.
Verbs commonly followed by a bare infinitive: querer, poder, deber, preferir, necesitar.
Practical tips for study
1) Create flashcards with the verb plus its preposition where necessary. Example front: alegrarse — back: alegrarse de + infinitive.
2) Read authentic Spanish texts and mark every time you see de before an infinitive; note the verb that governs it.
3) Practice speaking short sentences aloud, paying attention to whether the verb feels complete with or without de.
4) When in doubt, consult a reliable dictionary or grammar resource to confirm a verb’s preposition pattern.
Conclusion
Using de before infinitives correctly takes attention to verb patterns and meaning. Learn verbs as chunks with their prepositions, pay attention to emotion/doubt/obligation verbs, and contrast pairs like dejar vs dejar de and deber vs deber de. With exposure and focused practice, choosing when to use de will become natural.
