Past Perfect of the Subjunctive Mood

To form the "pretérito pluscuamperfecto" (past perfect) of the subjunctive mood, we need to use the auxiliary verb "haber" (have) in its "pretérito imperfecto" (past simple) of the subjunctive mood and the past participle of another verb. To form the past participle of the regular verbs in Spanish, we need to take the verb as we find it in the dictionary and remove the last two letters. Then, if the verb ends in "-ar" we will add the ending "-ado" and if the verb ends in "-er" or "-ir" we will add the ending "-ido". Eg:

For the verbs ending in -ar:

yo (I) Hubiera o hubiese
tú (You) Hubieras o hubieses
él, ella, usted (he, she, you formal) Hubiera o hubiese
nosotros, nosotras (we) Hubiéramos o hubiésemos
vosotros, vosotras (you all) Hubierais o hubieseis
ellos, ellas, (they) ustedes (you all formal) Hubieran o hubiesen