Lesson 29: Compound future and conditional

Part 1: The formula — same shape across all compound tenses

Every compound tense in French is built the same way:

auxiliary (avoir / être) in the relevant tense + past participle

Notice: the participle never changes. Only the tense of the auxiliary moves. English does exactly the same thing — I have / had / will have / would have eaten — except English uses one auxiliary (have) while French splits avoir and être.

Everything you learned in L21–22 and L24 still applies:

• Auxiliary choice — same rules (être house + reflexives → être; everything else → avoir).
• Participle agreement — same rules (with the subject under être; with the preceding direct object under avoir).

Part 2: Futur antérieur — "by the time X, I will already have…"

Conjugation

One-to-one with English: aurai parlé = "will have spoken". Serai parti = "will have left". The English form is literally will have + past participle.

When to use it

Action that will already be finished by a certain point in the future. In English this is "will have done":

• Quand tu arriveras, j'aurai déjà préparé le dîner. — When you arrive, I'll already have made dinner.
• Dans deux ans, ils auront fini leurs études. — In two years, they'll have finished their studies.
• Elle sera partie avant huit heures. — She'll have left before eight.

The main trigger: quand, dès que, une fois que, après que

If a when / as soon as clause and a main clause are both in the future, and one finishes before the other, the earlier-finishing one goes in futur antérieur, the later one in futur simple.

English-speaker trap! English cheats here: we say "When I finish the report, I'll call you" — both clauses look like present. French refuses to do that. The first clause is future in meaning, so it gets a French future form — and because it finishes first, it gets futur antérieur, not futur simple.

Compare:

• English: When I finish, I'll call. (present + future, both refer to future)
• French: Quand j'aurai fini, je t'appellerai. (futur antérieur + futur simple)

After après que, French uses the indicative (futur antérieur), not the subjunctive — unlike avant que, which takes subjunctive (coming in L34).

Secondary use: guessing about the past

Il n'est pas là. Il aura oublié. — He's not here. He must have forgotten. Tu as l'air fatigué — tu auras mal dormi. — You look tired — you must have slept badly.

English mirrors this with "must have + participle". This is a nuance, not the main use.

Part 3: Conditionnel passé — "I would have done X, but…"

Conjugation

Notice the auxiliary endings: -ais, -ais, -ait, -ions, -iez, -aient — same as imparfait, glued onto the future stem (aur-, ser-, ir-, fer-, viendr-…). That's how conditionnel is built (L28); just add the participle on top.

The English match is dead simple:

When to use it

1. Regret about the past ("I would have done it, but I didn't"):

• J'aurais aimé te voir hier. — I would have liked to see you yesterday (but I didn't).
• Elle serait venue, mais elle était malade. — She would have come, but she was sick.
• Nous aurions préféré un hôtel plus calme. — We would have preferred a quieter hotel.

2. Reproach — "should have / could have / would have" — the most useful pattern:

This is where English and French line up almost perfectly. Memorize these as fixed formulas:

Memorize as formulas: j'aurais dû / j'aurais pu / j'aurais voulu — three golden verbs of regret. These will be 80% of every conditionnel passé sentence you ever say. The map to English is so clean it almost feels like cheating:

• aurais dû = should have
• aurais pu = could have
• aurais voulu / aimé = would have liked

3. Unconfirmed information (journalism / hearsay):

Le président serait parti ce matin. — The president reportedly left this morning. Il y aurait eu un accident. — There may have been / is said to have been an accident.

The English equivalent is "reportedly / allegedly + verb" or "is said to have…".

4. Third type of si-clause (full lesson in L37):

When si + plus-que-parfait is paired with conditionnel passé, you get the "if I had… I would have…" pattern:

• Si j'avais su, je serais venu. — If I had known, I would have come.
• Si tu avais étudié, tu aurais réussi l'examen. — If you had studied, you would have passed the exam.

We'll dissect this in L37. For now, just lock the pairing: avais + participle → aurais + participle.

Part 4: All four compound tenses, side by side

See the system? Only the tense of the auxiliary changes. The participle is constant. Learn the participle once, and you get all four tenses for free.

Part 5: Participle agreement — same rules as before

Nothing new. The L24 rules carry over unchanged.