SUBJUNCTIVE or PRESENT? 1

Indicative for facts; subjunctive for subjectivity — The indicative states facts, certainties, and objective reality: Sé que viene. Es verdad que está cansado. The subjunctive expresses wishes, doubts, emotions, and hypotheticals: Quiero que vengas. Dudo que esté cansado. The key is the speaker's relationship to the reality of the event.

Creer que — a key example — Creer que triggers the indicative in affirmative sentences (belief = fact in the speaker's mind): Creo que tiene razón. But in negative sentences (doubt), it triggers the subjunctive: No creo que tenga razón. The same verb, two different moods — the polarity of the main clause determines which to use.

Cuando for future events — always subjunctive — When cuando refers to a future event, use the subjunctive: Cuando llegues, llámame (When you arrive — future). When cuando refers to a habitual or past event, use the indicative: Cuando llega, siempre trae flores (When he arrives — habitual). This asymmetry is frequently tested.