The extended conditional system: de + infinitive, hubiera and colloquial patterns

What it is

By B2 you can build the three standard conditionals: real (Si llueve, nos quedamos), hypothetical (Si lloviera, nos quedaríamos) and past counterfactual (Si hubiera llovido, nos habríamos quedado). Native speakers go further. Writers compress the si-clause into de + infinitive (De haberlo sabido, no habría venido); in conversation people swap the conditional for the imperfect or even the present (Si tuviera tiempo, me iba contigo; Si llegas cinco minutos antes, lo ves). This topic, the sistema condicional ampliado (extended conditional system), maps each variant to its register so you can recognise all of them and pick the one that fits.

How to form it

Three details make de + infinitive work:

• Pronouns attach to the infinitive: de haberlo sabido, de decírselo.
• An explicit subject goes after the verb: De haberlo sabido tu madre, no te habría dejado ir.
• No goes straight after de: De no haber llegado los bomberos…

The simple infinitive points to the present or the future, and the condition can be real (De seguir así…, if things go on like this) or hypothetical (De tener dinero, viajaría más). The compound infinitive is always a past counterfactual.

Hubiera can fill both clauses, and habría can replace it, but only in the main clause: si hubiera or si hubiese, never si habría. In the main clause, use hubiera or habría; hubiese there is less common, and many grammars advise against it.

When to use it

Choose by register: in an email to a client, De no ser por su ayuda…; to your cousin, Si no es por ti, me pierdo.

• De haberlo sabido, te habría avisado antes.Had I known, I would have told you sooner.formal, written
• De no ser por los vecinos, el incendio se habría extendido.If it hadn't been for the neighbours, the fire would have spread.de no ser por + noun
• De seguir lloviendo así, van a cerrar la carretera.If it keeps raining like this, they'll close the road.real condition
• Si me hubieras avisado, te hubiera ido a buscar.If you'd let me know, I'd have come to pick you up.hubiera in both clauses
• Si tuviera vacaciones, me iba a Oaxaca contigo.If I had time off, I'd go to Oaxaca with you.colloquial imperfect
• ¡Qué mala suerte! Si sales cinco minutos antes, no te agarra la lluvia.What bad luck! If you'd left five minutes earlier, the rain wouldn't have caught you.present = missed chance
• Que hace sol, comemos en el patio; que no, adentro.If it's sunny, we eat on the patio; if not, inside.colloquial alternatives
• Tú dile eso a tu abuela y vas a ver.You go and say that to your grandma and you'll see.imperative + y: threat

The colloquial patterns are not mistakes; most of them are everyday speech all over the Spanish-speaking world. They just don't belong in an essay, a report or a cover letter: in writing, go back to the conditional or up to de + infinitive. Latin American speech also uses iba a + infinitive in the main clause: Si no venimos, íbamos a quedar mal (if we hadn't come, we'd have looked bad).

Try it

Five quick exercises from this topic's training set:

Contrasts and traps

• Missed chance or real plan? Si llegas cinco minutos antes, lo ves can be a real condition about tomorrow or a lament about this morning. Context decides: ¡Qué lástima!, ya se fue or a past setting point to the counterfactual.
• No conditional after si. Si lo habría sabido is heard in some regions but is nonstandard everywhere: Si lo hubiera sabido.
• De no ser por, si no fuera por, si no es por. Same meaning, from formal to colloquial; the last one refers to the past: Si no es por ti, me pierdo. All three need por.
• Register clash. Me iba for me iría in a report reads as careless; de haberlo sabido in a text to a friend sounds bookish, though educated speakers do use it.
• Imperative + y. The C1 pattern (Abre la caja y verás) becomes a threat with an emphatic tú and verás / vas a ver: Tú vuelve a hacerlo y verás = Como vuelvas a hacerlo…

For Portuguese speakers

• Positive transfer. Brazilian speech also puts the imperfect in the main clause (Se eu tivesse tempo, ia com você), so Si tuviera tiempo, me iba contigo comes naturally. Keep both out of formal writing.
• The past counterfactual. Se eu soubesse, não tinha vindo is perfectly natural in Brazil; Spanish needs Si lo hubiera sabido, no habría venido (or no hubiera venido). Si lo supiera refers to now, and no había venido means "I hadn't come".
• Não fosse você has no preposition; Spanish needs por + ti: De no ser por ti, Si no fuera por ti.
• Pronoun position. Pra te ver puts the pronoun first; Spanish attaches it to the infinitive: de haberlo sabido, never de lo haber sabido.
• ter vs haber. Teria ido is habría ido, never tendría ido.
• Threats. Faça isso de novo pra você ver! → Hazlo otra vez y verás (with y, not para que veas).