The past subjunctive is used with the conditional tense to create contrary‐to‐fact speculation. “If I were the president, I would improve the country,” is an example of such a sentence in English. The same sentence can be written in the opposite order: “I would improve the country if I were the president.” The Spanish version uses the past subjunctive after the word “if” ( si) and puts the other verb in the sentence in the conditional tense. The formulas below are meant to demonstrate that regardless of in which order the sentence is written, the verb that follows si is in the past subjunctive and the other verb is in the conditional:
- si + past subjunctive + conditional
- Si ellos fueran más inteligentes, no comprarían esta casa.
- If they were smarter, they wouldn't buy this house.
- conditional + si + past subjunctive
- Ellos vendrían a mi fiesta si sus padres les permitieran.
- They would come to my party if their parents would permit them.
Another use of the past subjunctive is after the conjunction como si (“as if” in English). Although the verb in the first clause may be in almost any tense, the verb that follows como si is always in the past subjunctive because it means that what follows is contrary to reality.
- Ella hablaba como si fuera princesa.
- She was talking as if she were a princess.
- El gobierno gasta dinero como si no tuviera ningún límite.
- The government spends money as if it had no limit.