How and when do you use the pluperfect subjunctive?

The Pluperfect Subjunctive is used to indicate an action that happened prior to another in the past where the subjunctive is required. It is important to remember the acronym used for situations where the subjunctive is needed: ‘W.E.I.R.D.O’ which stands for ‘Wishes, Emotions, Impersonal Expressions, Requests, Doubt/Denial, Ojalá’. To form the Pluperfect Subjunctive we need to take the auxiliary verb ‘HABER’ in the Imperfect Subjunctive form, so: hubiera, hubieras, hubiera, hubiéramos, hubierais, hubieran. Then we follow this with the past participle of a verb, so those that end in –ADO/ -IDO/ irregulars. For example: the verb comprar in the yo form of the Pluperfect Subjunctive would be hubiera comprado. We use the Pluperfect Subjunctive to emphasise an action in the past that happened before another action, for example: ‘Me molestó que no me hubieras comprado un regalo de cumpleaños’. As the speaker has used an emotion in the past ‘me molestó que’ it triggers the use of the Pluperfect Subjunctive. The Pluperfect Subjunctive is also used in hypothetical clauses, also known as conditional ‘Si’ sentences. In these it refers to impossible situations as they are actions that have happened in the past and cannot be changed. An example of this is: ‘Si los estudiantes hubieran estudiado más, habrían sacado mejores notas’. It is used alongside the past conditional.