In short

The subjunctive has four tenses. You met the presente at step 38; here are the other three, and they are cheap because they are built from parts you already own. Congiuntivo passato (abbia fatto, sia partito) marks an action earlier than a present trigger; congiuntivo imperfetto (fossi, avessi, venisse) follows a past trigger or a conditional; congiuntivo trapassato (avessi fatto, fossi andato) is the past-behind-the-past. The forms are mechanical - the only genuinely new decision is which tense the trigger pulls.

The rule

Everything in step 39 still holds: some verb or expression must trigger the subjunctive (penso che, spero che, è possibile che, volevo che…). This lesson does not add new triggers; it adds the tenses you reach for once one has fired. The full timing system is step 49 and if-clauses are step 51 - here you learn to build the three tenses and to make the one basic choice.

Congiuntivo passato - the compound of the present subjunctive. Take the present subjunctive of the auxiliary (abbia or sia, from step 39) and add the past participle: abbia parlato, sia partito. The auxiliary choice and the participle agreement are exactly those of the passato prossimo (step 14): avere freezes the participle (abbia mangiato), essere agrees it with the subject (sia partita, siano partite). You use it when the trigger is in the present (or future) and the subordinate action is already over: Penso che Marco sia partito (I think Marco has left).

Congiuntivo imperfetto - a simple tense with its own endings. This is the one truly new form. To the stem add -ssi, -ssi, -sse, -ssimo, -ste, -ssero. The quickest way in: say the imperfetto indicativo io-form (step 19), cut the final -vo, and add -ssi. So parlavo -> parlassi, prendevo -> prendessi, dormivo -> dormissi, and the tricky stems fall out for free: facevo -> facessi, dicevo -> dicessi, bevevo -> bevessi, avevo -> avessi. Only three verbs refuse the trick and must be learned raw: essere -> fossi, dare -> dessi, stare -> stessi. As in the present subjunctive, io and tu are identical (io parlassi / tu parlassi), so the pronoun stays in.

Congiuntivo trapassato - the compound of the imperfetto subjunctive. Take the imperfetto subjunctive of the auxiliary (avessi or fossi) and add the participle: avessi parlato, fossi andato. Same auxiliary and agreement rules again. It is the subjunctive twin of the trapassato prossimo (step 31): a past that sits before another past.

The one choice you actually make. Once a trigger fires, two questions settle the tense:

• Step 1 - Is the trigger present-ish or past-ish? A trigger in the present or future opens the presente / passato pair. A trigger in a past tense (pensavo, volevo, era importante) or a conditional (vorrei, sarebbe meglio) opens the imperfetto / trapassato pair.
• Step 2 - Is the subordinate action at the same time, or earlier? Same time (or later) takes the simple tense of that pair (presente or imperfetto); earlier takes the compound one (passato or trapassato). So Penso che parta / Penso che sia partito, and in the past Pensavo che partisse / Pensavo che fosse partito.

That is the local rule in full. Note the conditional trigger: Vorrei che tu fossi qui (I wish you were here) - a conditional main verb reaches back for the imperfetto subjunctive, never the present indicative.

Forms & patterns

Congiuntivo passato - present subjunctive of the auxiliary + participle:

Congiuntivo imperfetto - the regular endings (note: io = tu):

The imperfetto-indicativo trick, and the three verbs that break it:

Congiuntivo trapassato - imperfetto subjunctive of the auxiliary + participle:

Which tense the trigger pulls - the basic local pairing:

Examples

Common mistakes

• Pensavo che era a casa. -> Pensavo che fosse a casa. A past trigger takes the imperfetto subjunctive, not the imperfetto indicative. era is the indicative; the subjunctive is fosse.
• Pensavo che sia partito. -> Pensavo che fosse partito. With a past trigger you shift back a level: the present-based sia partito belongs to a present trigger (penso che), while pensavo pulls the trapassato fosse partito.
• Volevo che tu venivi con noi. -> Volevo che tu venissi con noi. After volevo che the subjunctive is obligatory. venivi is the indicative; the imperfetto subjunctive is venissi.
• Speravo che noi arrivassero in tempo. -> Speravo che noi arrivassimo in tempo. The endings flip easily: noi ends in -ssimo, loro in -ssero. Keep them apart.
• Vorrei che tu sei qui. -> Vorrei che tu fossi qui. A conditional main verb (vorrei) opens the imperfetto pair, so it is fossi, never the present indicative sei.

Tips

• Two compounds, one simple tense. Congiuntivo passato = present subjunctive of the auxiliary (abbia / sia) + participle; congiuntivo trapassato = imperfetto subjunctive of the auxiliary (avessi / fossi) + participle. Own the present subjunctive from step 39 and the imperfetto endings below, and the compounds build themselves.
• The imperfetto hides in the imperfetto indicativo. Say the imperfetto indicativo io-form, cut -vo, add -ssi: parlavo -> parlassi, facevo -> facessi, bevevo -> bevessi. Only essere (fossi), dare (dessi) and stare (stessi) refuse - three words to memorise, and you are done.
• Trigger tense decides the pair; timing decides simple vs compound. Present/future trigger -> presente or passato; past trigger or a conditional (vorrei, sarebbe meglio) -> imperfetto or trapassato. Then pick the simple tense for “same time”, the compound for “earlier”.
• Wishes ride these tenses. Vorrei che… and Magari…! voice a wish with the imperfetto or trapassato subjunctive: Magari fossi ricco! (if only I were rich), Magari l’avessi saputo prima! (if only I had known sooner).