In short

You can now build the present subjunctive (Lesson 33) and you have met its uses (Lesson 34). This lesson sharpens the single decision that trips up English speakers most: after que, do I use the indicative or the subjunctive? The rule is about stance, not vocabulary. If the main clause asserts something as fact or as a firmly held opinion, the que-clause stays indicative: acho que ela tem razão (“I think she is right”). If the main clause casts the fact in doubt, denies it, or merely floats it as possible, the que-clause turns subjunctive: não acho que ela tenha razão, é possível que ela tenha razão. Watch the flip: acho que takes the indicative, but negate it to não acho que and the doubt it now carries pulls in the subjunctive. Three high-frequency triggers to lock in today: talvez (“maybe”), é possível que (“it is possible that”) and duvido que (“I doubt that”) are all subjunctive, while é verdade que (“it is true that”) stays indicative.

The rule

Certainty and assertion keep the indicative

When the speaker presents the content as real - a known fact or an opinion put forward as true - Portuguese uses the indicative, exactly as English keeps a plain statement:

• Fact / certainty: sei que, é verdade que, é certo que, é óbvio que, tenho a certeza de que.
• Opinion asserted as true: acho que, penso que, creio que, parece-me que.

Tenho a certeza de que o comboio parte às nove. (“I’m sure the train leaves at nine.”) The speaker is committing to it, so the verb is indicative.

Doubt, denial and possibility take the subjunctive

When the main clause weakens the truth of the que-clause - doubting it, denying it, or presenting it as only one possibility - the subjunctive appears:

• Doubt: duvido que.
• Denial: não é verdade que, nego que, não é que.
• Possibility / probability: é possível que, é provável que, pode ser que, talvez.

É possível que o comboio esteja atrasado. The lateness is not asserted, only entertained, so estar goes subjunctive (esteja).

Negation is the switch

This is the pattern to internalise. A verb of opinion is indicative when affirmative but flips to subjunctive when negated, because negating “I think…” turns an assertion into a doubt:

• Acho que ele vem. -> Não acho que ele venha.
• Penso que ela sabe. -> Não penso que ela saiba.

Questions usually keep the indicative, because a question does not itself deny anything: Achas que ele vem? (“Do you think he’s coming?“).

talvez and where “maybe” sits

talvez means “maybe” and normally stands before the verb, where it demands the subjunctive: Talvez chova amanhã (“Maybe it will rain tomorrow”). Because talvez is one of the adverbs that pull clitic pronouns in front of the verb (Lesson 30), you say Talvez te ligue logo (“Maybe I’ll call you later”), not ligue-te. Only when talvez comes after the verb does the indicative return (Chove, talvez), which is rarer and more literary.

é verdade que vs é possível que

The neat minimal pair to remember the whole lesson by: same subject, same verb, opposite mood, driven only by whether the frame asserts or merely allows.

Forms & patterns

Which mood the que-clause takes, by the stance of the main clause:

The minimal pair, one verb (estar), two frames:

Examples

Common mistakes

• Não acho que ela tem razão -> Não acho que ela tenha razão - negating an opinion verb turns it into a doubt, so the que-clause goes subjunctive.
• Talvez ela vem -> Talvez ela venha - talvez placed before the verb always requires the subjunctive.
• É possível que ele está doente -> É possível que ele esteja doente - possibility is not fact, so use the subjunctive.
• Duvido que tu tens tempo -> Duvido que tu tenhas tempo - duvidar expresses doubt and takes the subjunctive.
• É verdade que ele seja rico -> É verdade que ele é rico - a stated fact keeps the indicative; do not over-apply the subjunctive.
• Acho que ela tenha razão -> Acho que ela tem razão - an affirmative opinion asserts something, so it stays indicative.
• Talvez ligo-te logo -> Talvez te ligue logo - after talvez the clitic goes before the verb and the verb is subjunctive.

Tips

• Before you choose, ask one question: am I stating this as true, or flagging it as uncertain? True -> indicative; doubted, denied or merely possible -> subjunctive.
• Learn the certainty triggers as an indicative block: sei que, é verdade que, é certo que, é óbvio que, tenho a certeza de que, plus acho / penso / creio que while affirmative.
• Learn the doubt-and-possibility triggers as a subjunctive block: duvido que, talvez, é possível / provável que, pode ser que, não acho que, não é verdade que.
• Remember that negation is the switch: acho que (indicative) becomes não acho que (subjunctive), while a plain question keeps the indicative - Achas que ele vem?
• Anchor the whole rule on the pair é verdade que ele está cá vs é possível que ele esteja cá: same words, mood decided only by assert-vs-allow.
• In Brazil: the same logic holds, but casual speech often relaxes the flip after negation (you will hear não acho que ela tem…); in careful European Portuguese keep the subjunctive - não acho que ela tenha….