sem/antes de/depois de + Personal Infinitive

Infinitivo Pessoal Com Conjunções

Level 5

The Personal Infinitive (infinitivo pessoal) is used to clarify who is performing an action when using prepositions. Unlike the regular infinitive, it takes specific endings (-es, -mos, -em) to identify the subject.

How It Works

The personal infinitive is a 'hybrid' form: it looks like an infinitive but acts like a conjugated verb. It is most commonly triggered by prepositions like sem (without), antes de (before), and depois de (after).

1. Conjugation:
It is formed by adding these endings to the impersonal infinitive (the full dictionary form):

  • Eu: (no ending) - falar
  • Tu: -es - falares
  • Ele/Ela/Você: (no ending) - falar
  • Nós: -mos - falarmos
  • Vós: -des - falardes
  • Eles/Elas/Vocês: -em - falarem

2. When to use it:
Use it when the subject of the infinitive is different from the subject of the main verb, or whenever the subject is explicitly named to avoid ambiguity. For example: Eu saí sem eles saberem (I left without them knowing). Even if the subject is the same, you must use it if you explicitly state the pronoun: Para nós chegarmos a tempo, precisamos correr.

3. The Future Subjunctive Trap:
Note that the personal infinitive is always regular (based on the dictionary form). While it looks identical to the future subjunctive for regular verbs, they differ for irregulars. For example, the personal infinitive of 'ter' is termos, while the future subjunctive is tivermos.

4. Register:
In European Portuguese, this is used constantly in daily speech. In Brazil, it is a hallmark of educated speech and formal writing, while casual speech might simplify it or use a different construction.

Examples (4)

  1. Não saias sem nos avisares.

    Don't leave without letting us know.

    Word by Word: Not leave without us to-warn-you.

    The verb 'avisar' takes the '-es' ending because the subject is 'tu' (you).

  2. Lavem as mãos antes de comerem.

    Wash your hands before [you all] eat.

    Word by Word: Wash the hands before of to-eat-them.

    The ending '-em' clarifies that 'vocês' (you all) are the ones eating.

  3. Eles foram embora depois de a festa terminar.

    They left after the party ended.

    Word by Word: They went away after of the party to-finish.

    Even though 'terminar' looks like a normal infinitive, it is technically the 3rd person singular personal infinitive referring to 'a festa'.

  4. É melhor irmos agora para não chegarmos atrasados.

    It's better for us to go now so we don't arrive late.

    Word by Word: Is better to-go-us now for not to-arrive-us late.

    The '-mos' ending on 'ir' and 'chegar' clearly identifies 'nós' (we) as the subject.

Common Mistakes

  • Using the preterite stem for irregular verbs.

    Antes de eles fôrem embora.
    Antes de eles irem embora.

    Unlike the Future Subjunctive, the Personal Infinitive always uses the infinitive stem (ir), never the past stem (for-).

  • Adding 'que' before the personal infinitive.

    Antes que eles saírem.
    Antes de eles saírem.

    The word 'que' usually triggers the subjunctive mood. The personal infinitive follows prepositions like 'de' or 'sem' directly.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

sem/antes de/depois de + Personal InfinitiveLevel 5Infinitivo Pessoal Com Conjunções

Learn This First

To use the personal infinitive with 'sem', 'antes de', and 'depois de', you must first learn the conjugation of the personal infinitive itself. Additionally, you need to understand the logic of when to use the personal versus the impersonal infinitive, which typically depends on whether the subordinate clause has its own explicit or implied subject.

Words in This Pattern

depois de