Using the Future Subjunctive
Portuguese uses the Subjunctive mood to indicate something is uncertain to happen or to have occurred. There are 3 different degrees of uncertainty: (1) extremely unlikely, (2) plausible, (3) likely.
The Future Subjunctive is used for case (3): actions that are likely, yet have not yet occurred. Use this tense to talk about unceratin future events.
Call me when you arrive.
As soon as I buy a car, I'll go there.
These are all uncertain events. And, they're all in the future: planned or scheduled to occur.
In Portuguese these become,
The conjugation for the singular forms is easy – it’s just the infinitive form of the verb:
Me liga quando você chegar.
Se eu chegar atrasado, te aviso.
Assim que ela chegar nós podemos jantar.
As long as you stick to the eu, você, ele, ela, a gente forms, you are golden! If you're curious, you can look at the vocês, eles, elas, nós forms here.
Watch out for the irregular verbs! IR is one of the most common examples if this:
Triggers for the Future Subjunctive
The words, se and quando very often trigger this tense. Ask yourself: am I talking about action in the future (if, when, as soon as...) -? Most likely you need to switch on the future subjunctive.
if » se
when » quando
as soon as » assim que
Let's look at some common examples...
Examples of the Future Subjunctive
Forming the Future Subjunctive
The conjugation for the most used forms is simply: the infinitive of the verb!
*But of course that only works for regular verbs 😉 The true process for forming that works for all verbs is this: Take the preterit indicative (the simple past) PLURAL (vocês) and chop off the am ending.
falar: the plural past is, vocês falaram. Removeing the ending am it becomes » falar
comer » comer
abrir » abrir
Simply: the infinitive form. Easy peasy lemon squeezy!
Now look what we get with some irregular verbs:
ter: the plural past is, vocês tiveram. Removeing the ending am it becomes » tiver.
fazer » fizer
querer » quiser
ir » for
estar » estiver
ser » for
|if I arrive||se eu chegar|
|if he arrives||se ele chegar|
|if we arrive||se nós chegar||mos|
|if they arrive||se eles chegar||em|
|if I lose||se eu perder|
|If he loses||se ele perder|
|If we lose||se nós perder||mos|
|If they lose||se eles perder||em|
The whole point of the the subjunctive mood is to express situations that are less than a sure thing.
How about this?:
Here it's the CHEGAR that is treated with the future subjunctive. Again not very clear but, it's not clear that anyone is actually going talk until arriving home. The trigger here is até.
Here, we have PARAR in the future subjunctive. What's uncertain about this? I guess it's just that no one really knows if he's in fact going to work non-stop. Not very intuitive. If you had said "ele vai trabalhar sem parando" it would be wrong. You'd get strange looks.
It's the subjunctive that breaks so many students. They wither and then die. That, and the pronunciation of the language. Once you get the hang of the subjunctive conjugations, your destiny is clear: you will be a fluent speaker of Portuguese. Period.