Doing things without others knowing: Personal Infinitive with 'Sem'
Grammar Rule in 30 Seconds
Use 'sem' + personal infinitive to describe an action performed by someone while omitting another action.
- Use the personal infinitive form after 'sem' to specify the subject: 'Sem eles saberem' (Without them knowing).
- If the subject is the same as the main clause, you can use the impersonal infinitive: 'Saí sem comer' (I left without eating).
- Always conjugate the infinitive when the subject of the 'sem' clause differs from the main clause subject.
Overview
The Portuguese Personal Infinitive is a powerful grammatical construction that allows you to specify the subject of an infinitive verb, even within a dependent clause or after a preposition. While English typically resorts to gerunds (-ing forms) or full subordinate clauses to convey similar meaning, Portuguese offers a more concise and elegant solution by “conjugating” the infinitive itself. This C1-level rule is particularly crucial for articulating nuanced relationships between actions and their agents, especially when the subject of an embedded action differs from the main clause's subject.
Mastery of the personal infinitive, specifically with the preposition sem (without), is a hallmark of advanced Portuguese proficiency, enabling you to express complex ideas with precision and natural flow.
Fundamentally, the personal infinitive resolves ambiguity by explicitly marking who performs the infinitive's action. This stands in contrast to the impersonal infinitive, which is used when the subject of the infinitive is either the same as the main clause's subject or is generic and unspecified. Understanding this distinction is key to unlocking a more idiomatic and sophisticated command of Portuguese, particularly in formal discourse, professional settings, and literature.
How This Grammar Works
sem allows you to express an action that occurs (or, more accurately, doesn't occur) without a specific, stated subject performing it. The preposition sem (without) inherently implies a lack or absence. When followed by an infinitive, sem indicates that the action described by the infinitive did not happen, or that the main action occurred in the absence of the infinitive's action.Sem+ Impersonal Infinitive: Used when the subject of the action followingsemis the same as the subject of the main clause, or when the action has an indefinite/generic subject. For example,Eu saí sem comer.(I left without eating.) Here, botheu(I) andcomer(to eat) share the same subject.
Sem+ Personal Infinitive: This is employed when the subject of the action followingsemis different from the subject of the main clause. The infinitive verb is then inflected (or 'conjugated') to agree with this distinct subject. For instance,Eu saí sem eles verem.(I left without them seeing.) In this case,eu(I) is the subject ofsaí(left), whileeles(they) is the subject ofverem(seeing). The personal infinitiveveremclarifies that they were the ones not seeing.
sem que + subjunctive clause into a more streamlined prepositional phrase.Ele falou sem nós percebemos. (He spoke without us realizing.) The inflected infinitive percebemos directly links the action of not realizing to nós.Formation Pattern
-ar, -er, -ir) and add specific endings that correspond to the subject pronoun. Irregular infinitives generally maintain their stem irregularities.
-AR Verbs (falar) | -ER Verbs (comer) | -IR Verbs (partir) |
Eu | (no ending) | falar | comer | partir |
Tu | -es | falares | comeres | partires |
Ele/Ela/Você | (no ending) | falar | comer | partir |
Nós | -mos | falarmos | comermos | partirmos |
Vós | -des | falardes | comerdes | partirdes |
Eles/Elas/Vocês| -em | falarem | comerem | partirem |
Eu, Ele/Ela/Você): The form of the personal infinitive for these subjects is identical to the impersonal infinitive. Context, and often the explicit presence of the subject pronoun (e.g., sem eu saber), clarifies the subject. This is a common point of confusion for learners, but the explicit pronoun makes it unambiguous.
eu and ele/ela/você. For example, sem ele ir is clearer than just sem ir (which could mean 'without going' generally).
ter (to have) becomes teres (tu), termos (nós), terem (eles/elas/vocês). Similarly, pôr (to put) becomes pores, pormos, porem. There are few truly irregular personal infinitive endings once the stem is established.
ser (to be) and estar (to be), two fundamental irregular verbs:
SER (to be) | ESTAR (to be) |
Eu | ser | estar |
Tu | seres | estares |
Ele/Ela/Você | ser | estar |
Nós | sermos | estarmos |
Vós | serdes | estardes |
Eles/Elas/Vocês| serem | estarem |
When To Use It
sem with the personal infinitive is when the subject of the action following sem is explicitly different from the subject of the main clause. This is not merely a stylistic choice but often a grammatical necessity for clarity and correctness in C1-level Portuguese. Failing to use the personal infinitive in this scenario can lead to ambiguity or incorrect grammatical constructions.- Clarifying Distinct Subjects: This is the most common and obligatory use. Without the personal infinitive, the listener would likely assume the main subject is performing the action after
sem. Ela saiu da reunião sem nós sabermos.(She left the meeting without us knowing.) – Here,elais the subject ofsaiu, andnósis the subject ofsabermos.O projeto foi aprovado sem ele apresentar todas as propostas.(The project was approved without him presenting all the proposals.) –O projetois the subject offoi aprovado, whileeleis the subject ofapresentar.
- Emphasis on the Agent of Non-Action: Even when the context might be somewhat inferable, using the personal infinitive can add emphasis to the specific individual or group who failed to perform the action. This can be particularly useful in reporting or critical commentary.
A decisão foi tomada sem eles consultarem as partes interessadas.(The decision was made without them consulting the stakeholders.) – Highlightseles's oversight.
- Avoiding
sem que+ Subjunctive for Modern Usage: Whilesem quefollowed by the subjunctive is grammatically correct (sem que eles saibam), it is generally considered more formal, archaic, or literary in contemporary Portuguese, particularly in Brazil. The personal infinitive offers a more fluid, concise, and natural alternative for everyday communication, even in professional contexts. - Prefer:
Passamos a noite sem eles fazerem barulho.(We spent the night without them making noise.) - Less common (but grammatically sound):
Passamos a noite sem que eles fizessem barulho.
- After Other Prepositions (Connection to broader grammar): The personal infinitive isn't exclusive to
sem. It's a general feature of Portuguese grammar that appears after various prepositions (para,ao,por,antes de,depois de, etc.) when the infinitive has its own subject. Mastering it withsemprovides a transferable skill. A reunião é para vocês decidirem.(The meeting is for you all to decide.)Ao chegarmos ao local, encontramos a porta aberta.(Upon our arriving at the location, we found the door open.)
Common Mistakes
sem with the personal infinitive. Recognizing these common errors and understanding their underlying reasons will solidify your C1 proficiency.- Forgetting to Inflect the Infinitive: The most frequent error is using the impersonal infinitive when a distinct subject is present. This leads to grammatical incorrectness and often ambiguity.
- Incorrect:
Chegaram sem nós ver.(Implies they didn't see, or general 'without seeing' by the main subject) - Correct:
Chegaram sem nós vermos.(They arrived without us seeing.) - Why it's wrong: The form
veris the impersonal infinitive, implying the subject is eithereles/elas(they) or a generic 'one'. Sincenósis the intended subject ofver, inflection tovermosis mandatory.
- Confusion with
sem que+ Subjunctive: Whilesem que+ subjunctive is an alternative, it should not be indiscriminately swapped with the personal infinitive. Usingsem quecan sound overly formal, archaic, or even awkward in contexts where the personal infinitive is more natural. - Awkward/Formal:
Ele fez o trabalho sem que eu soubesse.(He did the work without me knowing.) - While grammatically sound, it's often more natural to use the personal infinitive. - More Natural:
Ele fez o trabalho sem eu saber. - Why it's a mistake (for C1 learners): At C1, the goal is not just grammatical correctness but also stylistic nuance. Over-reliance on
sem quecan make your Portuguese sound less contemporary or fluent.
- Incorrect Pronoun Placement (Clitics): With compound tenses or pronominal verbs, the placement of object pronouns (clitics) can be tricky. Generally, clitics attach after the personal infinitive in European Portuguese (
sem nos lembrarem), but in Brazilian Portuguese, they often precede the personal infinitive (sem nos lembraremorsem eles nos lembrarem). - Example (EP):
Eles foram embora sem se despedirem.(They left without saying goodbye.) - Example (BP preference):
Eles foram embora sem se despedirem.(Still common, but sometimessem eles se despediremis preferred for clarity). The rule issem [subject pronoun] [clitic] [personal infinitive]orsem [subject pronoun] [personal infinitive] [clitic]in EP depending on context. - Why it's tricky: Clitic placement is complex and varies significantly between dialects. When in doubt, ensure the main subject and the infinitive's subject are clear, and research specific clitic placement for complex constructions.
- Misinterpreting
Eu/Ele/Ela/VocêForms: Since the 1st and 3rd person singular forms of the personal infinitive are identical to the impersonal infinitive, learners sometimes omit the explicit subject pronoun, leading to ambiguity. - Ambiguous:
Saí sem saber.(Could mean 'I left without knowing' or 'I left without someone else knowing' ifsaberwas meant to be personal and the pronoun was omitted) - Clear:
Saí sem eu saber.(I left without me knowing.) - Clear:
Saí sem ele saber.(I left without him knowing.) - Why it's confusing: The uninflected form looks exactly like the impersonal infinitive. Including the pronoun
euorele/ela/vocêis crucial to specify the distinct subject, preventing misinterpretation.
Real Conversations
To truly master sem with the personal infinitive, observe how native speakers deploy it in various registers. This construction is ubiquitous, from casual chats to formal reports, precisely because it offers conciseness without sacrificing clarity.
- Casual Exchange (Texting/Chat):
- A festa começou sem eu saber que ia ter. (The party started without me knowing it was going to happen.)
- Eles me ligaram sem eu conseguir atender. (They called me without me being able to answer.)
- Chegamos lá sem ele ter terminado a apresentação. (We got there without him having finished the presentation.)
- Observation: Even in informal contexts, the explicit subject pronoun for eu and ele/ela/você is frequently retained to avoid ambiguity.
- Professional/Workplace Context (Emails/Meetings):
- A decisão foi tomada sem nós considerarmos todas as implicações. (The decision was made without us considering all the implications.)
- Por favor, não avancem com a proposta sem a equipa jurídica analisar os termos. (Please, do not proceed with the proposal without the legal team analyzing the terms.) – Note the use of a full noun phrase as the subject.
- Fizemos as alterações sem o cliente pedir quaisquer revisões adicionais. (We made the changes without the client asking for any additional revisions.)
- Observation: In professional settings, precision is paramount. The personal infinitive ensures that accountability (or lack thereof) is clearly assigned, making it an indispensable tool for formal communication.
- Social Commentary/News (More Formal):
- O governo implementou a nova lei sem a população ter sido devidamente informada. (The government implemented the new law without the population having been duly informed.) – Here, a passive personal infinitive is used (ter sido informada).
- A empresa foi vendida sem os funcionários terem qualquer aviso prévio. (The company was sold without the employees having any prior notice.)
- Observation: The personal infinitive is agile enough to handle complex subjects and even passive constructions, demonstrating its versatility and high utility in advanced discourse.
Quick FAQ
- Q: Is the personal infinitive with
semalways mandatory when subjects differ? - A: Yes, for grammatical correctness and clarity. While
sem que+ subjunctive is an alternative, the personal infinitive is the standard and most natural choice in contemporary Portuguese when the infinitive's subject is explicitly stated and differs from the main clause's subject.
- Q: Can I omit the subject pronoun (e.g.,
eu,eles) before the personal infinitive? - A: You can omit it if the context makes the subject absolutely clear, especially for
nós,tu,vós,eles/elas/vocês(due to their unique endings). However, foreuandele/ela/você(whose personal infinitive forms are identical to the impersonal infinitive), it is strongly recommended to include the pronoun to avoid ambiguity. For example,Saíram sem saberemclearly means 'They left without knowing', butSaí sem saberis ambiguous without context, soSaí sem eu saberorSaí sem ele saberclarifies.
- Q: Does this rule apply equally in Brazilian and European Portuguese?
- A: Yes, the personal infinitive is a fundamental and active grammatical feature in both major variants of Portuguese. Its usage patterns and importance are consistent across Brazil and Portugal.
- Q: How does this relate to other prepositions like
paraorao? - A: The same principle applies. When a preposition is followed by an infinitive that has its own distinct subject, that infinitive will take the personal infinitive form. For example:
Trouxe isto para vocês verem.(I brought this for you all to see.) orAo chegarmos em casa, ligamos a televisão.(Upon arriving home, we turned on the TV.). Mastering it withsemprovides a solid foundation for its use with other prepositions.
- Q: Are there exceptions where
sem que+ subjunctive is preferred? - A: In very formal or literary contexts, particularly when expressing a strong negative consequence or a counterfactual scenario,
sem que+ subjunctive might be chosen for its more formal tone. However, for most everyday and even professional communication, the personal infinitive is generally preferred for its conciseness. The choice is often stylistic, but the personal infinitive is almost always a safe and natural option.
Personal Infinitive Conjugation (Example: Saber)
| Person | Form |
|---|---|
|
Eu
|
saber
|
|
Tu
|
saberes
|
|
Ele/Ela/Você
|
saber
|
|
Nós
|
sabermos
|
|
Vós
|
saberdes
|
|
Eles/Elas/Vocês
|
saberem
|
Meanings
This construction allows the speaker to indicate that an action occurred while a specific person or group did not perform a secondary action.
Subject differentiation
Specifying who did not do something.
“Saí sem eles verem.”
“Ele assinou sem o advogado ler.”
General exclusion
General lack of action.
“Sem sabermos, tudo mudou.”
“Sem eles pedirem, ajudei.”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
sem + [Personal Infinitive]
|
Saí sem eles verem.
|
|
Negative
|
sem + não + [Personal Infinitive]
|
Saí sem não verem (rare/emphatic)
|
|
Question
|
sem + [Personal Infinitive] + ?
|
Saíste sem eles saberem?
|
|
Same Subject
|
sem + [Impersonal Infinitive]
|
Saí sem comer.
|
|
Plural Subject
|
sem + [Personal Infinitive Plural]
|
Saímos sem eles saberem.
|
|
Formal
|
sem + [Personal Infinitive]
|
Sem vós saberdes, agimos.
|
Formality Spectrum
Procedi sem o gestor saber. (Workplace)
Fiz sem o gestor saber. (Workplace)
Fiz sem o chefe saber. (Workplace)
Fiz sem o boss saber. (Workplace)
Personal Infinitive Logic
Same Subject
- Impersonal No conjugation
Different Subject
- Personal Conjugate verb
Examples by Level
Saí sem eles saberem.
I left without them knowing.
Comi sem tu veres.
I ate without you seeing.
Fiz sem eles pedirem.
I did it without them asking.
Entrei sem eles notarem.
I entered without them noticing.
Eles foram sem nós sabermos.
They went without us knowing.
Ela falou sem eles ouvirem.
She spoke without them hearing.
Trabalhei sem eles verem.
I worked without them seeing.
Saímos sem vós saberdes.
We left without you (plural) knowing.
O projeto avançou sem os sócios aprovarem.
The project moved forward without the partners approving.
Eles decidiram sem nós consultarmos.
They decided without us consulting.
A casa foi vendida sem os donos saberem.
The house was sold without the owners knowing.
Fizemos o plano sem eles participarem.
We made the plan without them participating.
A empresa tomou medidas sem os funcionários compreenderem.
The company took measures without the employees understanding.
Ele assinou o contrato sem o advogado lerem.
He signed the contract without the lawyer reading it.
Eles viajaram sem os pais permitirem.
They traveled without the parents allowing.
A lei foi aprovada sem a população debaterem.
The law was passed without the population debating.
O sistema foi alterado sem os desenvolvedores preverem as consequências.
The system was altered without the developers foreseeing the consequences.
Ela agiu sem os seus pares concordarem com a estratégia.
She acted without her peers agreeing with the strategy.
Eles concluíram a tarefa sem os supervisores fiscalizarem.
They finished the task without the supervisors inspecting.
A mudança ocorreu sem os moradores anteciparem o impacto.
The change occurred without the residents anticipating the impact.
A decisão foi ratificada sem os membros do conselho deliberarem.
The decision was ratified without the board members deliberating.
O autor publicou a obra sem os críticos avaliarem o manuscrito.
The author published the work without the critics evaluating the manuscript.
A crise eclodiu sem os analistas vislumbrarem a magnitude.
The crisis erupted without the analysts envisioning the magnitude.
O acordo foi selado sem as partes litigantes transigirem.
The agreement was sealed without the litigating parties compromising.
Easily Confused
Learners use personal when impersonal is needed.
They look the same.
Learners use it after 'sem'.
Common Mistakes
Saí sem eles saber.
Saí sem eles saberem.
Saí sem eu saber.
Saí sem saber.
Sem eles ver.
Sem eles verem.
Sem nós faze.
Sem nós fazermos.
Ele falou sem vós saber.
Ele falou sem vós saberdes.
Sem eles chegar.
Sem eles chegarem.
Sem ela verem.
Sem ela ver.
Sem os pais saber.
Sem os pais saberem.
Sem nós ter feito.
Sem nós termos feito.
Sem eles terem ido.
Sem eles terem ido.
Sem os membros do conselho deliberar.
Sem os membros do conselho deliberarem.
Sem as partes transigir.
Sem as partes transigirem.
Sem os analistas vislumbrar.
Sem os analistas vislumbrarem.
Sem o autor publicar.
Sem o autor publicar.
Sentence Patterns
Eu fiz ___ sem eles ___.
Eles saíram sem nós ___.
A lei passou sem a população ___.
O projeto foi finalizado sem os sócios ___.
Real World Usage
Postei a foto sem eles verem.
Saí sem eles saberem.
Tomei a decisão sem o gestor saber.
O contrato foi assinado sem as partes saberem.
O pedido saiu sem o cliente saber.
Comprei a passagem sem eles saberem.
Check the subject
Don't over-conjugate
Future Subjunctive
Clarity is key
Smart Tips
Conjugate the infinitive verb.
Use the simple infinitive.
Use the personal infinitive to ensure clarity.
Think of the future subjunctive.
Pronunciation
Suffix stress
The stress remains on the infinitive root, not the suffix.
Falling intonation
Saí sem eles saberem. ↘
Statement of fact.
Memorize It
Mnemonic
Sem-Subject-Suffix: If the subject changes, the suffix must change too!
Visual Association
Imagine a person walking through a door (Main Clause) while a group of people behind them are wearing masks (The 'sem' clause). Because the people behind are different from the walker, they need their own 'mask' (the suffix).
Rhyme
Se o sujeito mudar, a terminação tem que acompanhar.
Story
João entered the party. He wanted to surprise everyone. He walked in 'sem eles verem' (without them seeing). He hid behind a curtain. He waited 'sem eles saberem' (without them knowing).
Word Web
Challenge
Write 5 sentences about your day using 'sem' + personal infinitive to describe things others didn't notice.
Cultural Notes
Very common in daily speech to use the personal infinitive for clarity.
More formal usage, often preferred in writing.
Similar to Brazil, focus on clarity.
Derived from the Latin infinitive, the personal infinitive is a unique development in Ibero-Romance.
Conversation Starters
Já fizeste algo sem os teus pais saberem?
É possível trabalhar sem o chefe saber?
Consegues sair de casa sem os vizinhos verem?
Já assinaste algo sem o advogado ler?
Journal Prompts
Common Mistakes
Test Yourself
Saí sem eles ___.
Which is correct?
Find and fix the mistake:
Eles foram sem nós saber.
Saí sem ver. (Eles)
Saímos sem vós ___.
Match each item on the left with its pair on the right:
sem / eles / chegar / saímos
The personal infinitive is used when the subject is the same.
Score: /8
Practice Exercises
8 exercisesSaí sem eles ___.
Which is correct?
Find and fix the mistake:
Eles foram sem nós saber.
Saí sem ver. (Eles)
Saímos sem vós ___.
Nós -> ?
sem / eles / chegar / saímos
The personal infinitive is used when the subject is the same.
Score: /8
Practice Bank
10 exercisesO professor explicou sem os alunos ___ (entender).
Não desligues sem tu ___ (falar) comigo!
Match the pronoun to the verb suffix.
pagarem / saíram / eles / sem / .
O jantar acabou...
Fizemos tudo sem o chefe saberem.
Translate: Without us asking.
É impossível entrares sem eles ___ (abrir) a porta.
Which is correct for 'Without me going'?
Eles entraram sem nós ouvimos.
Score: /10
FAQ (8)
To avoid ambiguity about who is performing the action in a secondary clause.
Yes, the forms are identical, but the usage is different (factual vs hypothetical).
Yes, any verb can be conjugated in the personal infinitive.
The form is the same as the impersonal infinitive, so context is vital.
It is used in all registers, but essential in formal writing.
Because 'sem saber' is more natural when the subject is the same.
Yes, very frequently.
Try writing sentences about secrets or things happening without others knowing.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Sin + infinitive
Spanish lacks the personal infinitive.
Sans + infinitive
French does not conjugate the infinitive.
Ohne + zu + infinitive
German does not have a personal infinitive.
~nai de
Japanese verb conjugation is entirely different.
Bidun an + subjunctive
Arabic uses the subjunctive, not the infinitive.
Meiyou + verb
Chinese has no verb conjugation.
Learning Path
Prerequisites
Related Videos
Related Grammar Rules
Timing & Subjects: Using Personal Infinitive (antes/depois de)
Overview Ever sent a WhatsApp message saying `antes de sairmos` and wondered if you just sounded like a 19th-century poe...
Mastering the Personal Infinitive (Infinitivo Pessoal)
Overview The Personal Infinitive, or `Infinitivo Pessoal`, is one of the most distinctive and powerful features of the...
Formal & Literary Personal Infinitive (Infinitivo Pessoal)
Overview Ever felt like Portuguese was just trying to be different for the sake of it? While Spanish, French, and Italia...
The Personal Infinitive: Verbs with People Attached
Overview The Portuguese **Personal Infinitive** (`Infinitivo Pessoal`) represents a pivotal grammar concept for B2 learn...
Personal Infinitive: Conjugating Verbs After Prepositions (Infinitivo Pessoal)
Overview Portuguese is unique among many Romance languages for its **Personal Infinitive** (`Infinitivo Pessoal`). Unlik...
