Si clauses / hypotheticals
B1 L'hypothèse et les phrases avec si 36 / 52
In short
A si clause links a condition (the si part) to a result. French has three fixed patterns, and the golden rule is simple: the tense you put after si decides the tense of the result - and you never use a conditional or a future directly after si.
The rule
Every hypothetical sentence has two halves: the condition (introduced by si = “if”) and the result (the main clause). Either half can come first; when the si clause comes first, a comma separates them: Si j’ai le temps, je viendrai. / Je viendrai si j’ai le temps.
The whole system boils down to matching the tense after si with the tense of the result. There are exactly three types, from real to impossible.
Note on elision: si becomes s’ only before il and ils -> s’il pleut, s’ils viennent. It stays si before everything else, including elle: si elle vient.
Note on scope: the ban on a future or a conditional applies to the verb of the si clause itself. A que clause depending on it keeps the tense it needs: Si j’avais su qu’il viendrait, j’aurais attendu. (If I had known he would come, I would have waited.)
Type 1: si + présent -> présent / futur (real / likely)
Used for a condition that is real or very possible. The result is a general truth (present), an instruction (imperative), or a likely future outcome (futur simple).
- si + present -> present (general truth): Si tu chauffes l’eau, elle bout. (If you heat water, it boils.)
- si + present -> future (likely outcome): Si tu travailles, tu réussiras. (If you work, you will succeed.)
- si + present -> imperative (advice/order): Si tu es fatigué, repose-toi. (If you are tired, rest.)
Type 2: si + imparfait -> conditionnel présent (unreal / hypothetical present)
Used for a situation that is contrary to the present reality or unlikely. The si clause takes the imparfait, and the result takes the conditionnel présent (see Lesson 34).
- Si j’avais de l’argent, j’achèterais une maison. (If I had money, I would buy a house - but I don’t.)
- Si nous habitions à Paris, nous irions au Louvre chaque semaine.
- Careful: the imparfait here does not mean past time; it marks the hypothesis.
Type 3: si + plus-que-parfait -> conditionnel passé (unreal past / regret)
Used for a situation in the past that did not happen - typical for regrets and reproaches. The si clause takes the plus-que-parfait (Lesson 33), and the result takes the conditionnel passé (Lesson 35).
- Si j’avais su, je ne serais pas venu. (If I had known, I would not have come.)
- Si tu avais étudié, tu aurais réussi l’examen. (If you had studied, you would have passed the exam.)
- The two auxiliaries follow the usual rules: avoir for most verbs, être for movement/pronominal verbs, with past-participle agreement.
Forms & patterns
The three canonical structures - memorise the tense pairs:
| Type | Meaning | Si clause | Result clause |
|---|---|---|---|
| 1 | real / likely | présent | présent, futur, or impératif |
| 2 | unreal present | imparfait | conditionnel présent |
| 3 | unreal past | plus-que-parfait | conditionnel passé |
One verb, venir, across the three types:
| Type | Si clause | Result clause |
|---|---|---|
| 1 | si je viens | je viendrai |
| 2 | si je venais | je viendrais |
| 3 | si j’étais venu | je serais venu |
Note the near-identical Type 1 vs Type 2 forms - only one letter separates the future viendrai from the conditional viendrais, and only the stem vowel and the ending separate the present viens from the imperfect venais.
Examples
| Français | English |
|---|---|
| Si tu veux, on peut partir maintenant. | If you want, we can leave now. |
| Si vous finissez tôt, vous pourrez sortir. | If you finish early, you will be able to go out. |
| Si j’étais riche, je voyagerais partout. | If I were rich, I would travel everywhere. |
| Si elle parlait chinois, elle trouverait ce poste. | If she spoke Chinese, she would find that job. |
| Si nous avions su, nous serions restés à la maison. | If we had known, we would have stayed home. |
| Si tu avais écouté, tu n’aurais pas fait cette erreur. | If you had listened, you would not have made this mistake. |
| S’il pleut demain, le match sera annulé. | If it rains tomorrow, the match will be cancelled. |
| Si j’avais le temps, je t’aiderais. | If I had time, I would help you. |
Common mistakes
- Si je serais riche… -> Si j’étais riche… - never a conditional after si; use the imparfait.
- Si j’aurai le temps, je viendrai -> Si j’ai le temps, je viendrai - never a future after si; use the present.
- Si j’aurais su… -> Si j’avais su… - Type 3 takes the plus-que-parfait after si, not the conditional.
- Si il pleut -> S’il pleut - si elides to s’ before il/ils.
- Si elle venait, je serais content mixed as Si elle viendrait… -> Si elle venait… - keep the imparfait in the condition.
- Si tu as étudié, tu aurais réussi -> Si tu avais étudié, tu aurais réussi - match the pair: plus-que-parfait with conditionnel passé.
Tips
- Learn the three pairs as blocks: présent/futur, imparfait/conditionnel présent, plus-que-parfait/conditionnel passé.
- Iron rule: the verb of the si clause takes only the présent, imparfait, or plus-que-parfait - never a future or a conditional.
- Type 1 = it could really happen; Type 2 = it isn’t so now; Type 3 = it didn’t happen then (regret).
- si elides only before il/ils (s’il, s’ils), never before elle or elles.
- Word order is free: put the si clause first with a comma, or the result first with no comma.
- Don’t confuse this si (“if”) with si meaning “yes” (contradicting a negative) or “so” (si grand).