Conditional Sentences

If...

This word -which in English is used to express situations that will, might, could or would happen if a certain condition is met- is simply translated to Spanish into the word "Si..."

There are three different kinds of "Si..." conditionals:

1. Likely situations (present + present, future, or imperative)

2. Unlikely situations (imperfect subjunctive + conditional)

3. Impossible situations (pluperfect subjunctive + pluperfect subjunctive or conditional perfect)

The first verb tense listed is the one that follows Si (if), while the second tense is the "result clause" - the event that is dependent on the first. In English, the "result clause" is often preceded by then.


1) Likely Situations
Present + Present
Used for things that happen (regularly) when a condition is met.

Si llueve, no trabajamos. - If it rains, we don't work.

Miro la televisión si no quiero leer. - I watch TV if I don't want to read.

Present + Future
Used for events that will occur (in the future) if the condition is met (in the present).

Si tengo tiempo, yo lo haré. - If I have time, I will do it.

Si estudias, serás inteligente. - If you study, you will be smart.

Present + Imperative
Used to give an order (in the imperative) dependent on the condition being met (in the present).

Llama mañana si puedes. - Call tomorrow if you can.
(If you can't, then don't worry about it.)

Si Ud. tiene dinero, pague la cuenta. - If you have money, pay the bill.
(If you don't have money, someone else will do it.)


2) Unlikely Situations
In these cases, the situation described is not currently true. But if the situation changed, the result clause would be able to occur.
The condition clause (which starts with si) requires the imperfect subjunctive, while the result clause takes the conditional. The order of the clauses is unimportant.

For example...

Si tuviera dinero, iría contigo. - If I had money, I would go with you.
(I don't have any money so I can't go, but if I did [currently contrary], I would be able to.)

Podrías ver tu hermano si fueras con nosotros. - You could see your brother if you went with us.

(You say you don't want to go with us, so you won't see your brother, but if you did go with us [currently contrary], you would see him.)


3) Impossible Situations
The least common type of "Si..." clause: impossible situations. Used when referring to something that would have happened if some condition had been met. Since the condition was not met, the result clause is impossible.
The condition clause (which starts with si) requires the pluperfect subjunctive, while the result clause takes either the pluperfect subjunctive or the conditional perfect. The order of the clauses is unimportant.

For example...

Si hubiera sabido, hubiera ido contigo. - If I had known, I would have gone with you.
(I hadn't known, so I didn't go with you, but if I had [impossible], I would have.)

¿Hubieras (or habrías) comprado el libro si te hubiera dicho? - Would you have bought the book if I had told you?
(I hadn't told you, so you didn't by the book, but if I had [impossible], would you have?)