Setting Rules with First Conditionals
In Portuguese, when you talk about a future condition that is likely to happen — such as setting rules and their consequences — you use a "first conditional" sentence.
When the word se (if) introduces a future possibility, the verb immediately following it must be in the future subjunctive. The other half of the sentence (the consequence) is usually in the future tense, often using ir + infinitive.
| If you behave well, you will receive the allowance. | Se te portares bem, vais receber a mesada. |
| If he behaves badly, he will be grounded. | Se ele se portar mal, vai ficar de castigo. |
This structure works exactly the same way for negative conditions.
| If you do not obey, I will forbid the video game. | Se não obedeceres, vou proibir o videojogo. |
| If they disobey the teacher, the punishment will be strict. | Se eles desobedecerem ao professor, o castigo vai ser rigoroso. |
Irregular Verbs in Conditions
If the verb in the se clause is irregular, remember to use its irregular future subjunctive base. For example, the future subjunctive of fazer (to do/make) uses the base fizer-. This comes in handy when talking about children throwing a tantrum (fazer birra).
| If the boy throws a tantrum, we will forbid the candies. | Se o menino fizer birra, vamos proibir os rebuçados. |
Using Commands as Consequences
The consequence in a conditional sentence does not have to be in the future tense. You can also give an order or advice using the imperative. Just like in English, the se clause can come either at the beginning or the end of the sentence.
| Buy the video game if they behave well! | Compra o videojogo se eles se portarem bem! |
| If the little boy disobeys, do not keep the promise. | Se o menino desobedecer, não cumpras a promessa. |
