ao + Infinitive
Infinitivo Absoluto
The ao + infinitivo construction (Absolute Infinitive) is a sophisticated way to say 'when' or 'upon' in formal Portuguese. It sets the background for a main event.
How It Works
This construction is a sophisticated way to express 'when' or 'at the moment of'.
1. Meaning: It denotes simultaneity or immediate succession (precedence). It is most accurately equated to quando (when) or no momento em que (at the moment that).
2. Causal Nuance: Beyond time, this structure often carries a causal meaning, implying 'because' or 'since'. For example, Ao ouvir o barulho, ela acordou suggests she woke up because she heard the noise.
3. Structure:
- Ao + Impersonal Infinitive: Standard when the subject is the same as the main clause (e.g., Ao sair, ele fechou a porta).
- Ao + Personal Infinitive: Mandatory when the infinitive has its own explicit subject (e.g., Ao saírem os noivos, todos aplaudiram).
4. Regional Usage: In Portugal, this is a standard part of everyday speech. In Brazil, it is considered highly formal or literary; Brazilians usually prefer quando or the gerund in casual contexts.
5. The 'o' in 'ao': This is a fossilized element. It never changes to 'à' or 'aos' regardless of the nouns that follow.
Examples (5)
- Ao chegarem os convidados, a música começou a tocar.
Upon the guests' arrival, the music began to play.
Word by Word: To-the to-arrive the guests, the music started to play.
Here, the personal infinitive 'chegarem' is used because 'os convidados' is the explicit subject of the temporal clause.
- Ao ver a polícia, o ladrão fugiu.
Upon seeing the police, the thief fled.
Word by Word: To-the to-see the police, the thief fled.
This example shows both temporal succession and a causal nuance: he fled because he saw the police.
- Ao ser-lhe apresentada a proposta, o diretor hesitou.
When the proposal was presented to him, the director hesitated.
Word by Word: To-the to-be-to-him presented the proposal, the director hesitated.
Notice the formal enclisis (ser-lhe) which is common in this high-register pattern.
- Ao perceber o erro, ela corrigiu o texto imediatamente.
Upon noticing the error, she corrected the text immediately.
Word by Word: To-the to-notice the error, she corrected the text immediately.
In Brazil, a speaker might prefer the gerund ('Percebendo o erro...') for a more natural, less formal tone.
- Ao despontar a aurora, os viajantes puseram-se a caminho.
As dawn broke, the travelers set out on their way.
Word by Word: To-the to-break the dawn, the travelers put-themselves to path.
This demonstrates the literary use of the construction to set a scene.
Common Mistakes
Using the impersonal infinitive when a different subject is present.
Ao chegar os convidados, a festa começou.Ao chegarem os convidados, a festa começou.If the subject of the infinitive (the guests) is different from the main clause, you must use the personal infinitive (chegarem).
Using this construction for long-duration actions.
Ao viver em Lisboa, aprendi muito.Enquanto vivia em Lisboa, aprendi muito.This construction denotes the specific moment an action starts or occurs (punctual), rather than a continuous duration. Use 'enquanto' for ongoing states.
How It Connects
Learn This First
To understand the 'ao + infinitivo' absolute construction, a learner must first be comfortable with the contraction 'ao' and the use of the infinitive verb form. Since this construction often functions as a temporal or circumstantial clause (meaning 'upon' or 'when'), familiarity with the standard 'ao + infinitive' structure is a necessary foundation before applying it in more formal, independent narrative contexts.
- Infinitivo Pessoal x Impessoal
Understanding the base form of the verb (infinitive) is essential as it is the core component of this construction.
Level 4 - ao + Personal InfinitiveUpon Doing with Personal Infinitive
The absolute construction is a specific syntactic use of the 'ao + infinitive' structure, which the learner should already be familiar with in its basic temporal sense.
Level 3
Related Patterns
- Personal Infinitive
This construction frequently utilizes the personal infinitive to clarify the subject of the temporal action.
Level 3 - Gerúndio Absoluto
In Brazil, the gerund absolute is often preferred over this construction to express simultaneous actions.
Level 6 - a + o = aoContraction Ao
This pattern relies on the fixed contraction 'ao' as a temporal marker.
Level 1 - Enclisis (Pronoun After Verb)
Because this is a formal structure, it is often paired with enclitic pronoun placement.
Level 2 - quando + Future SubjunctiveQuando (Futuro Do Subjuntivo)
This is the standard alternative used in casual speech to express future temporal conditions.
Level 4
Learn Next
Patterns that build on this one.
Words in This Pattern
Practice ao + Infinitive in Bubblegum
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