SI CLAUSES
As mentioned in your past perfect subjunctive lecture notes, si clauses are used to express contrary to fact conditions. For such clauses there is a very definite sequence of tenses to be followed. Note the following examples:
Haré el viaje si tengo el dinero. (I will make the trip if I have the money).
Haría el viaje si tuviera el dinero. (I would make the trip if I had the money).
Habría hecho el viaje si hubiera tenido el dinero. (I would have made the trip if I had had the money).
The sequence of tenses is as follows:
| Main Clause | Si Clause |
| Future Indicative | Present Indicative |
| Conditional | Imperfect Subjunctive |
| Conditional Perfect | Past Perfect Subjunctive |
*keep in mind that they will not always appear in this order….the present indicative may appear first, in which case you need to follow it with the future. The imperfect subjunctive may appear first [see below],and should be followed with the conditional, etc..this is because sometimes the si clause appears before the main clause.
Naturally, there are exceptions to the rule!! Many speakers of Spanish substitute the past perfect subjunctive for the conditional perfect in the main clause:
Hubiéramos hecho el viaje si hubiéramos tenido el dinero (Instead of Habríamos hecho el viaje si hubiéramos tenido el dinero).
Si yo ganara la lotería estaría muy feliz. (¡o sería un milagro!)
Si yo fuera un hombre, trataría a las mujeres con mucho respecto.
Si nosotros tuviéramos la oportunidad de estudiar al extranjero, saldríamos en seguida.
***for more info on si clauses see the Lecture Notes for the Past Perfect Subjunctive and sequence of tenses info section ***