the Future Subjunctive

Portuguese Future Subjunctive
Use

The future subjunctive is used to talk about future actions that are not completely sure to happen. Such as,

As soon as I get off work, I’ll call you.
When I get to the beach, we’ll go surfing.
If you talk to Raquel, tell her I’m at home.

In Portuguese these become,

Assim que eu sair do serviço, te ligo.
Quando eu chegar na praia, a gente vai surfar.
Se você falar com Raquel, diga para ela que estou em casa.

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.

Watch out for the irregular verbs! IR is one of the most common example if this:

Se você for a praia, leva protetor solar.
Quando eu for ao centro eu vou procurar uma loja de móveis.
Triggers

If, when and as soon as often trigger this tense.  Ask yourself: am I talking about action in the future? If your'e saying if, when or as soon as -- use the future subjunctive.

Forming

For regular verbs only the plural forms change from the infinitive.

-ar future subjunctive regular verbs
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
-er and -ir future subjunctive regular verbs
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
Less Obvious Cases

The whole point of the subjunctive is to express situations that are less than 100% certain to occur. Look at these examples though:

Ele vai trablahar sem parar. > He's going to work without stopping.

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.

Bem, que tal esse:

Eu vou falar até chegar em casa. > I'm going to talk until I get (arrive) home.

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.

It's the subjunctive that breaks so many a student. 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.

Learn about the other subjunctive forms here: the Present Subjunctive and the Imperfect Subjunctive.