The past conditional (condicional pasado) represents, as its name implies, the past of the present conditional tense. Both the present and past conditional express hypothetical situations or conditions.
The past conditional is a compound tense, like present perfect and pluperfect, meaning that it has two parts: an auxiliary and the past participle. The past conditional is formed with the conditional of the auxiliary haber and the past participle of the main verb, as seen in the table below.
|hablar to speak
|yo habría hablado
|nosotros/as habríamos hablado
|tú habrías hablado
|él/ella/usted habría hablado
|ellos/as/ustedes habrían hablado
Like the present conditional, the past conditional is used for hypotheses. Unlike the present conditional, however, it is used to describe or imagine events and actions which failed to happen. This is why it is often used to express regret about events which did not occur. In most cases, the past conditional is translated as meaning would have in English. However, habría podido means I could have; habría debido I should have, habría querido means I would have likedSon puertas que yo nunca en mi vida habría podido haber imaginado.
They are doors that I would have never been able to imagine in my life.
The past conditional is found in si clauses with the pluperfect subjunctive. This is because si clauses with the pluperfect subjunctive also describe events that did not occur, or rather conditions which were not fulfilled so that the event in the past conditional could occur.
Si hubiera estudiado más, habría sacado una nota mejor en el examen de español.If I had studied more, I would have got a better grade in the Spanish test.
For more details about hypothetical clauses see also the page about si clauses.