The subjunctive, and what forces it

How the Spanish present subjunctive is formed, the triggers that require it, and the contrast with the indicative.

Trigger + que + Subjunctive

Certain expressions are followed by que, and the verb after that que has to take this form.

Forming it

Take the yo form of the present, drop the -o, and add the opposite vowel. -ar verbs take -e; -er and -ir take -a.

Building it from the yo form carries the irregularity along: tengo → tenga, hago → haga, conozco → conozca.

Wanting, needing, doubting, feeling, and impersonal judgements — when the two halves have different subjects.

Quiero que vengas.

I-want that you-come

I want you to come.

Spanish has no want someone to do something construction. It must go through que.

Quiero tú venir.

Quiero que vengas.

Spanish cannot put a subject between querer and an infinitive. Where the two subjects differ, the sentence needs que and the subjunctive.

When both halves share a subject, no que and no subjunctive: quiero venir.

Ser → sea. Ir → vaya. Saber → sepa. Haber → haya. Estar → esté. Dar → dé.

Espero que sea fácil.

I-hope that it-be easy

I hope it’s easy.

Creo que viene. / No creo que venga.

I-believe that he-comes / not I-believe that he-come

I think he’s coming. / I don’t think he’s coming.

The negative introduces doubt, and the doubt is what triggers the subjunctive.

From Arabic inshallah, and one of the most useful words in Spanish.

Ojalá haga sol mañana.

hopefully it-make sun tomorrow

I hope it’s sunny tomorrow.