The Infinitive
Uses of the infinitive: after verbs, prepositions, as subject…
The Infinitive (L'infinitif)
The infinitive is the base form of the verb (manger, finir, prendre). The real difficulty is almost never "which form is the base form" — it's which preposition goes in front: à, de, or nothing at all? These three patterns follow no logical rule and must be learned in chunks.
💡 Intuition: the infinitive never changes shape — it's a Lego brick that plugs in anywhere. The hard part is finding the right connector (à / de / ∅) to attach it. 🏠 Memory aid: sort the common verbs into three piles — modals (vouloir/pouvoir/devoir/aller) that plug in bare-handed; "heading toward doing" (commencer à, apprendre à) take à (à carries a sense of direction); "finishing / letting go" (finir de, décider de, arrêter de) take de.
1. After a conjugated verb (no preposition)
| Verb | Example |
|---|---|
| vouloir | Je veux partir. (I want to leave.) |
| pouvoir | Tu peux venir. (You can come.) |
| devoir | Il doit travailler. (He must work.) |
| savoir | Elle sait nager. (She knows how to swim.) |
| aimer | J'aime lire. (I like to read.) |
| aller (near future) | Je vais manger. (I'm going to eat.) |
| venir de (recent past) | Je viens d'arriver. (I just arrived.) |
2. Verb + de + infinitive
| Verb | Example |
|---|---|
| essayer de | J'essaie de comprendre. (I'm trying to understand.) |
| oublier de | Il a oublié de fermer la porte. (He forgot to close the door.) |
| décider de | Nous avons décidé de partir. (We decided to leave.) |
| refuser de | Elle refuse de répondre. (She refuses to answer.) |
3. Verb + à + infinitive
| Verb | Example |
|---|---|
| commencer à | Il commence à pleuvoir. (It's starting to rain.) |
| apprendre à | J'apprends à conduire. (I'm learning to drive.) |
| réussir à | Elle a réussi à passer l'examen. (She managed to pass the exam.) |
4. After prepositions
| Preposition | Example |
|---|---|
| pour | Je travaille pour réussir. (I work to succeed.) |
| sans | Il est parti sans dire au revoir. (He left without saying goodbye.) |
| avant de | Avant de partir, vérifie tout. (Before leaving, check everything.) |
| après + past inf. | Après avoir mangé, il est sorti. (After eating, he went out.) |
5. As subject
Voyager est enrichissant. (Traveling is enriching.)
6. Negation of the infinitive
Both negative elements go before the infinitive:
Je préfère ne pas sortir. (I prefer not to go out.) Il m'a dit de ne rien dire. (He told me not to say anything.)
7. Past infinitive
avoir/être + past participle
Après avoir fini ses devoirs, il a joué. (After finishing his homework, he played.)
⚠️ The #1 trap: à, de, or nothing before the infinitive?
To say "want to do" versus "start to do," French demands different prepositions; picking the wrong one is the favorite trap of TCF multiple-choice questions:
| Direct (∅) | + à | + de |
|---|---|---|
| vouloir (want) | commencer (start) | finir (finish) |
| pouvoir (can) | apprendre (learn) | essayer (try) |
| devoir (must) | réussir (succeed) | décider (decide) |
| aller (going to) | aider (help) | oublier (forget) |
| aimer (like) | se mettre (set about) | accepter (agree) |
🔑 Compare with the same travailler: Je veux travailler / Je commence à travailler / J'essaie de travailler. The form never moves; only the connector changes. The rules are finite — memorize high-frequency pairings in chunks.
⚡ TCF Tip
The infinitive frequently appears in TCF in preposition choices (de/à/pour + inf.) and reading comprehension (signs, instructions).