Les phrases avec si
French si (if) clauses come in three flavors, each with a fixed tense pairing. Get the pairing right and you sound like a native; mix them up and you sound off. The three types ladder from realistic (might happen) to hypothetical (probably won't) to counterfactual (already didn't, no take-backs). Crucially: the si clause itself never uses futur or conditionnel — those tenses live only in the result clause.
Type 1 — real / likely: si + présent → futur (or présent)
When the condition is realistic — something that genuinely might happen — pair si + présent with the futur simple in the result. Si j'ai le temps, je viendrai. = If I have time, I'll come. Si tu travailles, tu réussiras. = If you work, you'll succeed. The result can also stay in the present for general truths or a more immediate plan: Si tu veux, on part maintenant. = If you want, we leave now. The imperative is also possible: Si tu vois Marie, dis-lui bonjour. = If you see Marie, say hi to her.
Type 2 — hypothetical / unlikely: si + imparfait → conditionnel présent
When the condition is contrary-to-reality-now or just unlikely, pair si + imparfait with the conditionnel présent. Si j'avais le temps, je viendrais. = If I had time, I would come. (But I don't have time right now.) Si j'étais riche, j'achèterais une maison. = If I were rich, I would buy a house. Si tu pouvais, tu m'aiderais? = If you could, would you help me? This is the same construction as English 'if I were…, I would…'. NOTE: French uses imparfait here, NOT subjonctif. Never si je sois — always si j'étais.
Type 3 — counterfactual past: si + plus-que-parfait → conditionnel passé
For things that already didn't happen — past regrets, alternate-history scenarios — pair si + plus-que-parfait (preview of lesson 29) with the conditionnel passé. Si j'avais su, je serais venu. = If I had known, I would have come. (But I didn't know, and I didn't come.) Si tu m'avais appelé, j'aurais répondu. = If you had called me, I would have answered. The plus-que-parfait is avoir/être imparfait + past participle (j'avais su, j'étais allé). The conditionnel passé is avoir/être conditionnel + past participle (je serais venu, j'aurais répondu). Both use the same auxiliary as the passé composé.
Mixed type — past condition, present consequence
You can mix Type 3 condition with Type 2 result when a past event still has present consequences: Si j'avais étudié, je parlerais français maintenant. = If I had studied, I would speak French now. The condition is past-counterfactual (plus-que-parfait), but the result is about the present (conditionnel présent). Less common, but worth recognizing.
Order doesn't matter — pairings do
You can flip the clauses freely, with no change in meaning. Je viendrais si j'avais le temps. = Si j'avais le temps, je viendrais. Same pairing, just reordered. When the si clause comes second, no comma is needed. When the si clause comes first, a comma usually separates them. The CRITICAL thing is to keep the tenses correctly paired — never mix Type 1 with Type 2.
What si never gets
si itself NEVER takes the future, the conditional, or the subjunctive. Always présent, imparfait, or plus-que-parfait. Wrong: si je viendrai, si je viendrais, si je vienne. Right: si je viens, si je venais, si j'étais venu. The future and conditional live only in the result clause.
