Portuguese Infinitive Complements Explained After Common Verbs

Introduction

Understanding how infinitives work after verbs is essential for sounding natural in Portuguese. This article explains the use of the infinitive as a complement after common verbs in Brazilian Portuguese, showing patterns, variations, and useful examples for English-speaking learners at beginner to intermediate levels.

What is the infinitive in Portuguese?

The infinitive is the basic, unconjugated form of a verb. In Portuguese, regular infinitives end in -ar, -er, or -ir, for example: falar, comer, partir. The infinitive can act as a noun, the main verb, or a complement after another verb. Here we focus on the infinitive used as a complement after common verbs.

Infinitive forms: personal and impersonal

Portuguese has two infinitive forms: the impersonal infinitive (the basic form) and the infinitivo pessoal (the personal infinitive). The impersonal infinitive is used most often after common verbs like querer, poder, precisar. The personal infinitive is used when the infinitive needs to agree with subjects in certain constructions, often after prepositions or conjunctions like para, sem, antes de, desde que.

Why English speakers need to pay attention

In English we often use to + verb (to eat, to go) or the gerund (eating, going). Portuguese uses the infinitive instead, and some verbs allow different structures. Learning which verbs take an infinitive directly, which need a preposition, and when to use the infinitivo pessoal helps avoid common mistakes and makes speech smoother.

Common verbs that take the infinitive directly

Some verbs in Portuguese are commonly followed directly by an infinitive without any preposition. These are typically verbs of desire, intention, perception, or ability. Below are groups with explanations and examples.

Verbs of desire and intention: querer, desejar, preferir

These verbs take the infinitive directly when expressing want or preference. The subject of the main verb is usually the same as the subject of the infinitive.

Examples:

Eu quero estudar hoje.
Ela deseja viajar nas férias.
Nós preferimos ficar em casa.

Note that if the subject changes, Portuguese often uses que + conjugated verb instead of changing the infinitive subject:

Eu quero que ele estude hoje. (I want him to study today)

Verbs of perception: ver, ouvir, sentir

Verbs of perception can be followed by an infinitive to indicate an action observed or perceived. This is similar to English I saw him leave.

Examples:

Eu vi Pedro sair do prédio.
Nós ouvimos o menino chorar ontem.

When the action is ongoing, Portuguese often uses the gerund instead: Eu vi o menino chorando.

Ability and permission: poder, conseguir

Verbs that express ability, permission, or capacity also take the infinitive directly.

Examples:

Ela pode falar três idiomas.
Eu consigo correr cinco quilômetros.

Other verbs commonly followed by the infinitive

Outros verbos incluem começar, continuar, aprender, ensinar, prometer, tentar. These verbs typically combine with an infinitive to express actions, attempts, or future plans.

Examples:

Ele começou a trabalhar cedo. (Note that começar frequently uses a with the infinitive: começar a + infinitive)
Vou continuar estudar. (More natural: Vou continuar a estudar or Continuarei estudando)

Prepositions and the infinitive: when you need a preposition

Certain verbs require a preposition before the infinitive. The most common prepositions are de and a. The choice of preposition can change with register or meaning, so pay attention to fixed verb-preposition combinations.

Verbs that take de + infinitive

Verbs like esquecer, terminar, recusar, and ter medo often use de before an infinitive.

Examples:

Ela esqueceu de ligar para mim.
Ele terminou de trabalhar às oito.
Eles têm medo de voar.

Note that esquecer can also be followed by que + clause when the subject changes: Esqueci que ela vinha hoje.

Verbs that take a + infinitive

Some verbs use a + infinitive, such as começar in many contexts, and ir (to be going to) in periphrastic future constructions.

Examples:

Vou ir a estudar depois. (Common: Vou estudar depois; but a + infinitive appears in some fixed expressions)
Ela começou a estudar cedo.

Many learners find a vs de confusing. Memorize common verb-preposition pairs and listen to native speech to internalize usage.

The infinitivo pessoal: when the infinitive must agree

The infinitivo pessoal is used when the infinitive has its own subject that differs from the main clause subject or when the subject is clear and needs to be marked. It inflects to agree with persons: eu, tu, ele/ela, nós, vós, eles/elas. It is common after prepositions like para, sem, antes de, depois de, ao, and with conjunctions like quando or enquanto when there’s a change of subject.

Examples showing agreement

É importante eles chegarem cedo. (It is important that they arrive early)
Antes de sairmos, precisamos de desligar as luzes. (Before we leave, we need to turn off the lights)
Para ela aprender, precisa praticar todos os dias.

Notice the infinitive endings change: chegar becomes chegarem and sair becomes sairmos. This marks that the subject of the infinitive is different or explicitly identified.

When is the personal infinitive optional?

When the subject of the infinitive is the same as the main clause subject, the impersonal infinitive is often used and the personal form is optional or unnecessary. Context and emphasis determine the choice. Formal writing and clarity favor the personal form when ambiguity exists.

Comparison:

Eu quero ir ao mercado. (Same subject; impersonal)
Ela prefere nós irmos juntos. (Different subject explicit or emphasis on the we)

Negative infinitives and pronoun placement

Negation with infinitive complements follows normal rules: place não before the verb or before the auxiliary expression. When using object pronouns, Brazilian Portuguese generally places pronouns before the infinitive, especially in spoken language.

Examples:

Eu não quero sair hoje.
Ela vai me ajudar. (informal spoken: Vai me ajudar)
Ela vai ajudar-me. (written and more formal; in Brazil, proclisis me ajudar is more common)

With infinitives and clitic pronouns, modern Brazilian usage favors proclitic placement: quero te ver, vou te ligar. In some formal written contexts, especially in Portugal, enclisis (ver-te) or mesoclisis can appear, but Brazilian learners should prioritize the Brazilian norm.

Common pitfalls and how to avoid them

There are predictable mistakes English speakers make. Below are the most frequent and how to fix them.

Using the wrong preposition

Mixing up de and a is common. Learn verb-preposition collocations and practice them in context. If in doubt, consult a good dictionary or mirror native examples.

Forgetting the infinitivo pessoal when subjects differ

When the infinitive has a different subject, use the personal infinitive to avoid ambiguity. If unsure, rephrase with que + conjugated verb: Quero que ele venha instead of Quero ele vir.

Overusing the gerund

Portuguese uses the infinitive where English might use a gerund or to-infinitive. Don’t translate literally. Remember that verbs like querer, poder, dever, começar are usually followed by an infinitive.

Natural sentence-building tips

Practice common patterns rather than isolated verbs. Learn combinations like querer + infinitive, precisar de + infinitive, lembrar de + infinitive, começar a + infinitive. Focus on everyday phrases and listen to Brazilian Portuguese in context (conversations, TV, podcasts) to capture rhythm and placement of pronouns.

When constructing sentences, ask two questions: who is doing the action of the infinitive, and is that the same as the main clause subject? If different, consider the infinitivo pessoal or rephrase with que + subjunctive or indicative.

Cultural and usage notes

Brazilian Portuguese prefers simpler constructions in spoken language. You will often hear impersonal infinitives and proclitic pronoun placement. Formal written Portuguese may use the personal infinitive more and place pronouns after the verb. Regional differences exist, but everyday Brazilian speech prioritizes clarity and ease. Popular media and conversation are good sources for typical usage.

Also note politeness and formality influence verb choice. For example, using the infinitive with por favor or gostaria de + infinitive sounds more polite: Eu gostaria de saber se você pode ajudar.

Quick reference: common verbs and patterns

Below is a short list of frequent verbs and their typical infinitive patterns for quick review:

quero + infinitive: Eu quero viajar.
poder + infinitive: Você pode ajudar?
precisar de + infinitive: Eu preciso de comprar pão. (Also: Preciso comprar pão)
começar a + infinitive: Ela começou a trabalhar cedo.
esquecer de + infinitive: Ele esqueceu de fechar a porta.
ver + infinitive: Nós vimos eles sair.
prometer + infinitive: Eu prometo voltar amanhã.

More examples with explanations

Example 1: Maria quer estudar medicina.
Explanation: querer + infinitive; subject of both verbs is Maria.

Example 2: Pedro viu Ana sair do cinema.
Explanation: ver + infinitive indicates perception of an action; no preposition needed.

Example 3: Temos medo de voar.
Explanation: ter medo de + infinitive uses de before the infinitive.

Example 4: Antes de sairmos, trancamos a porta.
Explanation: antes de requires the impersonal or personal infinitive depending on subject; here the subject is nós, so sairmos (personal infinitive) is common.

Example 5: É importante eles chegarem cedo.
Explanation: personal infinitive used because the infinitive has explicit subject different from the main clause impersonal expression.

Resources for further learning

To internalize these patterns, combine dictionary study with listening practice. Pay attention to common verbs and how native speakers link subjects and infinitives. Reading Brazilian news, watching telenovelas or YouTube, and using graded readers will expose you to realistic usage of infinitive complements.

Conclusion

Mastering infinitive complements in Brazilian Portuguese improves fluency and reduces translation errors. Remember which verbs take the infinitive directly, which require prepositions, and when to use the infinitivo pessoal. Practice with real sentences and listen to native speech to make these structures natural in your own conversation.