French grammar · Advanced
Semi-Auxiliary Verbs in French: The Verbs That Modify Other Verbs
A semi-auxiliary is a fully conjugated verb that joins an infinitive and adds a shade of time, aspect, or attitude rather than a meaning of its own. Aller places an action just ahead, venir de places it just behind, être en train de holds it in progress, and devoir, pouvoir and vouloir add obligation, possibility and intention.
Je viens de rentrer et je vais me coucher.
I've just got home and I'm going to bed.
What it is
French has only two true auxiliaries, avoir and être, and their job is to build compound tenses. Semi-auxiliaries are something else: real verbs with real meanings that have been recruited to shade the verb beside them. They keep their own conjugation, which is why French can express the near future without inventing a new tense.
Elle vient de finir, elle est en train de ranger, et elle va partir. — She has just finished, she is tidying up, and she is going to leave.
How to spot it
Two verbs in a row, the first conjugated and the second in the infinitive, with the first contributing timing rather than an action of its own.
- Je viens d'arriver. — I've just arrived.
- Nous sommes en train de manger. — We're in the middle of eating.
- Il va falloir décider. — A decision is going to have to be made.
- Elle a failli tomber. — She nearly fell.
The test is whether the first verb still means what it usually means. In je vais partir, aller is not describing movement at all.
Semi Auxiliary Verbs Quick Reference
The semi-auxiliaries and what each one adds
| Semi-auxiliary | What it adds | Example |
|---|---|---|
| aller + infinitive | the near future | je vais sortir — I'm going to go out |
| venir de + infinitive | the recent past | je viens de sortir — I've just gone out |
| être en train de | an action in progress | je suis en train de sortir — I'm going out right now |
| être sur le point de | something imminent | je suis sur le point de sortir — I'm about to go out |
| devoir + infinitive | obligation or likelihood | je dois sortir — I have to go out |
| pouvoir + infinitive | ability or permission | je peux sortir — I can go out |
| faire + infinitive | causing an action | je fais sortir le chien — I'm letting the dog out |
| faillir + infinitive | a near miss | j'ai failli sortir — I nearly went out |
Common Semi Auxiliary Verbs Examples in French
Semi-auxiliaries grouped by what they contribute:
Timing
- Je viens de lui parler.
- I've just spoken to him.
- On va commencer dans dix minutes.
- We're going to start in ten minutes.
- Ils sont sur le point de signer.
- They're about to sign.
- Elle était en train de dormir.
- She was asleep at the time.
These four cover a fine-grained timeline that French has no separate tenses for: just before, in progress, about to, and shortly after.
Attitude and Modality
- Tu dois te reposer.
- You need to rest.
- Je ne peux pas y aller.
- I can't go.
- Il veut tout recommencer.
- He wants to start over.
- Elle sait piloter un avion.
- She can fly a plane.
These are the semi-auxiliaries that overlap with what English calls modals, and they behave exactly like the timing ones structurally.
Causing and Allowing
- Il a fait réparer sa voiture.
- He had his car repaired.
- Laisse-moi t'expliquer.
- Let me explain.
- On l'a laissé partir.
- They let him go.
- Le bruit fait fuir les oiseaux.
- The noise scares the birds away.
Faire makes the action happen; laisser permits it to. Both take a bare infinitive and both put the person after it.
Beginning, Continuing, Ending
- Il s'est mis à pleuvoir.
- It started raining.
- Elle continue à travailler.
- She's still working.
- Nous avons fini par accepter.
- We ended up accepting.
- Il ne cesse de se plaindre.
- He never stops complaining.
This group needs a preposition — à, de, or par — which is the main way it differs from the others.
How Semi-Auxiliaries Behave
They keep their own conjugation, they hand the meaning to the infinitive, and they take negation and pronouns in predictable places.
The Semi-Auxiliary Carries All the Grammar
Tense, person and mood live entirely in the first verb. The infinitive never changes, no matter how far into the past or the future the sentence goes.
Nous allions partir quand le téléphone a sonné.
We were about to leave when the phone rang.
Conjugate the first, freeze the second.
Some Take a Preposition, Most Do Not
Aller, devoir, pouvoir, vouloir, savoir, faire, laisser and faillir join the infinitive directly. Venir de, être en train de, se mettre à and finir par need their linking word, which is part of the expression.
Je vais essayer, mais je viens de commencer.
I'm going to try, but I've only just started.
Learn the preposition with the expression.
Negation Closes Around the Conjugated Verb
Ne and pas surround the semi-auxiliary, leaving the infinitive outside. In a compound tense they close around the auxiliary instead.
Je ne vais pas y aller.
I'm not going to go.
ne + semi-auxiliary + pas + infinitive.
Object Pronouns Attach to the Infinitive
Pronouns belong to the verb whose object they are, and that is normally the infinitive. They therefore slot in between the two verbs.
Tu dois le lui rendre.
You have to give it back to him.
semi-auxiliary + pronouns + infinitive.
Faire and Laisser Break the Pronoun Rule
In the causative construction the two verbs behave as a single block, so the pronoun jumps in front of faire or laisser rather than sitting between them.
Je le fais entrer.
I'm letting him in.
je le fais entrer, not je fais le entrer.
Common Mistakes with Semi Auxiliary Verbs
Incorrect: Je viens partir. — I've just left.
Correct: Je viens de partir. — I've just left.
The recent past requires de. Without it the sentence reads as venir in its ordinary sense of coming, which gives a completely different meaning.
Incorrect: Je suis en train partir. — I'm in the middle of leaving.
Correct: Je suis en train de partir. — I'm in the middle of leaving.
Être en train de is a fixed expression and the de cannot be dropped. It links the frozen noun train to the infinitive that follows.
Incorrect: Je vais partais. — I was about to leave.
Correct: J'allais partir. — I was about to leave.
The tense goes on the semi-auxiliary, not on the second verb. To move the sentence into the past you conjugate aller in the imperfect and leave partir alone.
Incorrect: Je fais le entrer. — I'm letting him in.
Correct: Je le fais entrer. — I'm letting him in.
Faire and its infinitive form a single unit, so the pronoun goes in front of the whole block rather than between the two verbs.
The Timeline Semi-Auxiliaries Build
French has no continuous tense and no perfect tense in the English sense. Three semi-auxiliaries fill those gaps, and shifting them into the imperfect moves the whole scale into the past.
Anchored to now
Conjugated in the present, these three place an action just before, during, or just after the moment of speaking.
| Pronoun | venir de (just before) | être en train de (right now) | aller (just ahead) |
|---|---|---|---|
| je / j' | je viens de partir | je suis en train de partir | je vais partir |
| tu | tu viens de partir | tu es en train de partir | tu vas partir |
| il / elle / on | il vient de partir | il est en train de partir | il va partir |
| nous | nous venons de partir | nous sommes en train de partir | nous allons partir |
| vous | vous venez de partir | vous êtes en train de partir | vous allez partir |
| ils / elles | ils viennent de partir | ils sont en train de partir | ils vont partir |
Venir de and être en train de are used only in the present and the imperfect. There is no *je viendrai de partir.
Anchored to a past moment
Put the semi-auxiliary in the imperfect and the whole scale slides backwards, relative to some other past event rather than to now.
| Pronoun | venait de | était en train de | allait |
|---|---|---|---|
| je / j' | je venais de partir | j'étais en train de partir | j'allais partir |
| tu | tu venais de partir | tu étais en train de partir | tu allais partir |
| il / elle / on | elle venait de partir | elle était en train de partir | elle allait partir |
| nous | nous venions de partir | nous étions en train de partir | nous allions partir |
| vous | vous veniez de partir | vous étiez en train de partir | vous alliez partir |
| ils / elles | ils venaient de partir | ils étaient en train de partir | ils allaient partir |
J'allais partir quand il est arrivé is the standard way to say I was about to leave when he arrived.
The rest of the family
These do not shift a sentence in time; they change how the action is presented. Each one keeps its own preposition.
| Pronoun | nuance | exemple |
|---|---|---|
| faillir | a near miss | j'ai failli oublier |
| se mettre à | a sudden start | il s'est mis à courir |
| finir par | an eventual outcome | elle a fini par céder |
| continuer à | persistence | il continue à fumer |
| ne faire que | doing nothing else | tu ne fais que critiquer |
| être sur le point de | imminence | nous sommes sur le point de partir |
Faillir survives almost only in the passé composé. J'ai failli tomber is idiomatic; je faillis tomber is not.
Stacking Semi-Auxiliaries
Because they are ordinary verbs, semi-auxiliaries can be piled on top of one another, and French does this far more readily than English.
Two or three in a row
Only the first verb is conjugated. Everything after it stays in the infinitive, however long the chain becomes.
- Je vais devoir partir.
- I'm going to have to leave.
- Tu dois pouvoir le faire.
- You must be able to do it.
- Elle va vouloir tout savoir.
- She's going to want to know everything.
- On va commencer à répéter demain.
- We're going to start rehearsing tomorrow.
English cannot say I will must leave, because its modals are defective. French has no such restriction.
With a compound infinitive
A semi-auxiliary can govern a past infinitive, which puts the second action before the first in time.
- Il doit avoir oublié.
- He must have forgotten.
- Elle semble être partie tôt.
- She seems to have left early.
- Tu aurais dû me prévenir.
- You should have told me.
Tu aurais dû plus an infinitive is the standard reproach: you should have. The participle dû keeps its circumflex.
Where the pronouns land in a chain
Object pronouns attach to the infinitive they belong to, which in a chain means they sit immediately before the last verb.
- Je vais devoir le lui dire.
- I'm going to have to tell him about it.
- Tu ne vas pas pouvoir y aller.
- You're not going to be able to go.
- Elle a dû vouloir nous aider.
- She must have wanted to help us.
Negation still closes around the first, conjugated verb, however many infinitives follow it.
Semi Auxiliary Verbs FAQs
- What is a semi-auxiliary verb in French?
- A conjugated verb followed by an infinitive, where the first verb adds timing, aspect or attitude instead of its own meaning. Aller, venir de, être en train de, devoir, pouvoir, vouloir, faire and laisser are the main ones.
- How are semi-auxiliaries different from avoir and être?
- Avoir and être take a past participle and build a compound tense that the grammar already recognises. Semi-auxiliaries take an infinitive and create meanings the tense system does not have, such as the near future or an action in progress.
- Do all semi-auxiliaries need a preposition?
- No. Aller, devoir, pouvoir, vouloir, savoir, faire, laisser and faillir join the infinitive directly. Venir de, être en train de, être sur le point de, se mettre à and finir par carry a preposition that is part of the expression.
- Can you use two semi-auxiliaries together?
- Yes, and French does it constantly: je vais devoir partir, tu dois pouvoir le faire. Only the first verb is conjugated, and every verb after it stays in the infinitive.
- Where do the pronouns go?
- In front of the infinitive they belong to: je vais le voir, tu dois me le rendre. The exception is faire and laisser, where the pronoun moves in front of the conjugated verb instead: je le fais entrer.