Subjunctive in Hypothetical and Negative

The subjunctive mood lives in the world of the subjective. It handles emotions, doubts, and possibilities. When you use a negative trigger, you change the reality of the sentence. For example, "I think he is here" is a fact to you. But "I do not think he is here" introduces doubt. In Portuguese, that doubt requires the subjunctive. The same applies to hypothetical situations. These are things that have not happened yet. Or things that might never happen. You are building a world of "could be" and "might have been." It sounds complex, but it follows a logical rhythm. Once you hear the trigger, your brain will start to flip the switch automatically. It is like learning to ride a bike with no hands. It feels scary until it suddenly clicks.

1. 1To use this rule, you need two main tenses: the Present Subjunctive and the Imperfect Subjunctive.
2. 2For the Present Subjunctive, start with the "eu" form of the present indicative.
3. 3Drop the "o" ending.
4. 4Add the opposite vowel. For -ar verbs, use e. For -er and -ir verbs, use a.
5. 5For the Imperfect Subjunctive, look at the third-person plural of the Pretérito Perfeito.
6. 6Remove the -ram ending.
7. 7Add the suffix -sse.
8. 8Example: Falar becomes fale (present) or falasse (imperfect).
9. 9Example: Comer becomes coma (present) or comesse (imperfect).
10. 10Remember, the imperfect form always has that distinct double "s." It sounds like a gentle hiss. It is the sound of a dream or a hypothetical wish.

You use this pattern in three main scenarios. First, use it after negative expressions of opinion. Phrases like não acho que or não creio que are classic triggers. Second, use it for hypothetical "if" clauses. This usually involves se paired with the imperfect subjunctive. For example, "If I had money, I would buy a boat." In Portuguese: Se eu tivesse dinheiro.... Third, use it with conjunctions that imply a condition. Words like caso (in case) or contanto que (as long as) always want the subjunctive. Imagine you are at a job interview. You might say, "In case you need more info..." That is Caso precise de mais informações.... It sounds professional and precise. It shows you understand the nuance of possibility.

Do not use the subjunctive when you are certain. If you say Acho que ele vem, you use the indicative. You are expressing a belief you hold as true. Do not use it after se when talking about the future in a likely way. That requires the Future Subjunctive, which is a different beast. Also, avoid it with verbs of certainty like saber or ter a certeza. If you say Tenho a certeza que ele ganha, keep it indicative. Using the subjunctive there would make you sound very confused. It would be like saying "I am 100% sure that he maybe wins." Your listener's head might spin. Stick to the facts when the facts are clear.

The biggest trap is forgetting the trigger. Many learners use the indicative after não acho que because they do it in English. In English, we say "I don't think he is." In Portuguese, you must say Não acho que ele seja. Another mistake is mixing up the tenses in hypothetical sentences. You cannot pair se eu tivesse with a present tense verb. It must pair with the conditional: Se eu tivesse, eu faria. Think of them as dance partners. They have to move together. If one steps left, the other must follow. Also, watch out for irregulars like dar, estar, and ser. They like to break the rules just to keep you on your toes.

Compare embora (although) and apesar de (despite). Embora triggers the subjunctive: Embora ele seja rico.... Apesar de usually takes the infinitive: Apesar de ele ser rico.... They mean the same thing, but the grammar changes. It is like choosing between a suit and a tuxedo. Both are formal, but they have different rules. Another contrast is talvez. In Portugal, talvez almost always takes the subjunctive. In Brazil, you might hear the indicative in casual speech. But for C1 level, stick to the subjunctive. It shows you have class. It shows you know the high-level architecture of the language.