'SI' CLAUSES - Past perfect subjunctive + Conditional Perfect 1

Past hypotheticals: past perfect subjunctive + conditional perfect — To express something that didn't happen in the past: Si + past perfect subjunctive → conditional perfect. Si hubiera estudiado, habría aprobado (If I had studied, I would have passed — but I didn't study). Both clauses refer to the past.

Forming the past perfect subjunctive — Hubiera/hubiese + past participle: hubiera hablado, hubiera comido, hubiera vivido. Irregular participles: hubiera hecho, hubiera dicho, hubiera visto, hubiera puesto. The hubiera form is more common; hubiese is the literary alternative, especially in Spain.

Mixed conditionals — mixing past and present — Sometimes the condition is in the past but the consequence is present: Si hubiera estudiado medicina, ahora sería médico (If I had studied medicine, I would now be a doctor). The si-clause uses the past perfect subjunctive; the main clause uses the simple conditional — this mixture is called a "mixed conditional".