As previously mentioned, the futuro do conjuntivofuture subjunctive allows us to talk about the conditions that must be met in order for a potential future action to occur, (i.e. “If this goes well, I will do that” or “When we get home, I will do that”). This tense appears in subordinate adverbial clauses (i.e. clauses which function like an adverb), as well as in relative clauses. It often goes along with the conjunction se if or others such as:
- assim que as soon as, once
- sempre que whenever
- quando when
- enquanto while, as long as
- como how
- o quewhat
With regular verbs, the futuro do conjuntivo is conjugated exactly the same as the infinitivo pessoal (personal infinitive). All you need to do is add the correct terminations to the infinitive, without removing any letters. Both the 1st and 3rd person singular stay exactly the same as the infinitive itself, making the endings as follows: (none), –es, (none), –mos, –em.
Here’s an example of how to conjugate the regular verbs comer to eat and falar to speak:
|se ele / ela / você||comer||falar|
|se eles / elas / vocês||comerem||falarem|
Regarding irregular verbs, you might find the following shortcut useful: Conjugate the verb in the 3rd person plural of the pretérito perfeito (simple past tense), remove the -am ending, then add the same endings shown above, according to each subject: (none), -es, (none), -mos, -em. Let’s try it out with the irregular verb ser:
- Conjugate the verb in the 3rd person plural simple past tense: foramthey went
- Drop the -am ending: for-
- Now, make it hypothetical! To put it in the futuro do conjuntivo, add a conjunction (such as se) and find the correct ending depending on who we’re talking about:
se eu forif I go
se tu foresif you go
se ela forif she goes
se nós formosif we go
se eles foremif they go
Se levares o carro, tens de pôr gasolinaIf you take the car, you have to put gas in it
Assim que chegarem, avisemAs soon as you pl. arrive, let me know
Enquanto for estudante, tenho descontoAs long as I'm a student, I get a discount
Faz como quiseresDo it however you want
Quando tiver fome, faço o almoçoOnce I'm hungry, I'll make lunch
Futuro do Conjuntivo vs. Imperfeito do Conjuntivo
You will probably come across a lot of “if” statements in both the imperfeito do conjuntivo and the futuro do conjuntivo, since both can be used to talk about potential future actions. So how do you know when to use which tense?
The difference is that the imperfeito version typically goes along with “if” when talking about a completely hypothetical situation, i.e. something that is unrealistic or unlikely to take place / to have taken place. The futuro version, on the other hand, is usually used along with “if” to talk about a likely or inevitable outcome.
Se eu for passear, vais comigo?If I go for a walk, will you go with me? futuro do conjuntivo
Se eu fosse passear, ias comigo?If I went for a walk, would you go with me? imperfeito do conjuntivo
While they’re both hypothetical, in the first example, the subject is seriously thinking about going for a walk in the near future. In the second example, the speaker may want to know how the listener feels about walks in general, his company, and/or if they’d join him on a walk some (unspecified) day.
Futuro do Conjuntivo vs. Infinitivo Pessoal
Many (but not all!) irregular verbs are going to have a different conjugation in the infinitivo pessoal (personal infinitive) and the futuro do conjuntivo. However, as we said earlier, regular verbs share the same conjugation in both tenses. So how can you tell the difference between the two? As usual, context is key! Remember that the futuro do conjuntivo is generally used to talk about the conditions that need to be met for a likely outcome to occur.
Conjunction + Futuro do Conjuntivo
As such, the conjunctions used in the sentence can sometimes give you a clue. The futuro do conjuntivo must be preceded by a conjunction, whereas the infinitivo pessoal does not (necessarily) have to. For example:
- Infinitivo pessoal: É melhor vocês porem a mesaIt's better you pl. set the table, You pl. had better set the table
- Futuro do conjuntivo: É melhor se forem vocês a pôr a mesaIt's better if you were the ones to set the table
In the first example, the focus is on you (pl.) doing the action, i.e. commenting that this is something you should do. In the second example, it’s about commenting on the hypothetical possibility of you (pl.) being the ones to do the action, as opposed to someone else doing it. Thus, you can see how they are similar, but the second makes the meaning more conditional.
Para + Infinitivo Pessoal
While we’re on the subject, let’s talk about when the personal infinitive can be preceded by a conjunction. While the future subjunctive appears in adverbial and relative clauses, the personal infinitive appears in substantive ones, preceded by the conjunction para and with verbs that indicate an order. Let’s try it with the regular verb começar:
- Infinitivo pessoal: Ele disse para começares de comerHe told you to start eating
To use the same verb in the future subjunctive, the conjugation is the same, but notice that we needed to make a few changes, and even added another clause to the sentence, in order to discuss a potential outcome based on the condition that “you start eating”:
- Futuro do conjuntivo: Ele disse que, se começares a comer, fala contigoHe said that if you start eating, he'll talk to you.