Using French Semi-Auxiliary Verbs

The most common auxiliary verbs are avoir and être. These are the conjugated verbs that stand in front of another verb in compound tenses to indicate mood and tense. In addition to these two, French has a number of semi-auxiliary verbs, which are conjugated in order to express various nuances of time, mood, or aspect. These verbs are followed by an infinitive. Some semi-auxiliary verbs are equivalent to modal verbs in English and some are verbs of perception. Here are the uses and meanings of some frequently used French semi-auxiliary verbs.

Aller

In present or imperfect tense, aller means "to be going to."

Je vais étudier.

I'm going to study.

J'allais étudier.

I was going to study.

In any tense, aller means "to go to/and."

Va chercher les clés.

Go and look for the keys.

Je suis allé voir mon frère.

I went to see my brother.

In any tense, aller is used to emphasize the verb that follows.

Je n'irai pas répondre à cela.

I'm not going to dignify that with a response.

Je vais te dire une chose.

Let me tell you something.

Devoir

In any tense, except conditional and past conditional, devoir indicates obligation or necessity.

J'ai dû partir.

I had to leave.

Tu dois manger.

You must eat.

In conditional form, devoir means "should." In past conditional, devoir means "should have."

Je devrais partir.

I should leave.

Il aurait dû nous aider.

He should have helped us.

Faillir

Fallir indicates that something almost happened.

Il a failli tomber.

He almost fell.

J'ai failli rater l'examen.

I nearly failed the test.

Faire

Causative construction: to make something happen, to have something done, to make someone do something.

J'ai fait laver la voiture.

I had the car washed.

Il me fait étudier.

He's making me study.

Laisser

To let something happen, to let someone do something.

Vas-tu me laisser sortir?

Are you going to let me go out?

Laisse-moi le faire.

Let me do it.

Manquer 

Followed by optional de, manquer indicates that something was about to happen or nearly happened.

J'ai manqué (de) mourir. 

I almost died.

Elle a manqué (de) pleurer. 

She nearly cried.

Paraître 

Paraître means to appear/to seem to.

Ça paraît être une erreur.

That appears to be an error.

Il paraissait être malade.

He seemed to be sick.

Partir

Partir means to leave, in order to, to go to.

Peux-tu partir acheter du pain?

Could you go out and buy some bread?

Il est parti étudier en Italie.

He went to study in Italy.

Passer

Passer means to call/drop in on, to call for, to go to.

Passe me chercher demain.

Come pick me up tomorrow.

Il va passer voir ses amis.

He's going to drop in on his friends.

Pouvoir

Pouvoir means can, may, might, to be able to.

Je peux vous aider.

I can help you.

Il peut être prêt.

He might be ready.

Savoir

Savoir means to know how to.

Sais-tu nager?

Do you know how to swim?

Je ne sais pas lire.

I don't know how to read.

Sembler

Sembler means to seem/to appear to.

Cela semble indiquer que…

That seems to indicate that…

La machine semble fonctionner.

The machine appears to be working.

Sortir de

Sortir de means to have just done something (informal).

On sort de manger.

We just ate.

Il sortait de finir.

He had just finished.

Venir

Venir means to come (in order) to.

Je suis venu aider.

I've come to help.

venir à

To happen to.

David est venu à arriver.

David happened to arrive.

venir de

To have just done something.

Je viens de me lever.

I just got up.

Vouloir

Vouloir means to want to.

Je ne veux pas lire ça.

I don't want to read that.

Veux-tu sortir ce soir?

Do you want to go out tonight?

When Avoir and Être Also Act as Semi-Auxiliary Verbs

When followed by à + infinitive, avoir means "to have to."

Avoir à

Vous avez à répondre.

You have to respond.

J'ai à étudier.

I have to study.

Être

Être à

To be in the process of.

Es-tu à partir?

Are you leaving?

Être censé

To be supposed to.

Je suis censé travailler.

I'm supposed to work.

Être en passe de

To be about to (usually indicates something positive).

Je suis en passe de me marier.

I'm about to get married.

Être en train de

To be in the process of, to be doing something right now.

On est en train de manger.

We're eating (right now).

Être loin de

To not be about/going to.

Je suis loin de te mentir.

I'm not about to lie to you.

Être pour

To be ready/prepared/willing to.

Je ne suis pas pour voler.

I'm not willing to steal.

Être près de

To be about to, ready to.

Es-tu près de partir?

Are you about to leave?

Être sur le point de? 

To be about to (positive or negative).

Il est sur le point de tomber. 

He's about to fall.

French Helping Verbs

Any verb that can be followed by an infinitive may be a semi-auxiliary, including (but not limited to):

• adorer: to adore doing
• aimer: to like, love doing
• (s')arrêter de: to stop doing
• chercher à: to look to do
• choisir de: to choose to do
• continuer à/de: to continue to do
• croire: to believe (that one) does
• demander de: to ask to
• désirer: to desire to
• détester: to hate doing
• dire (à quelqu'un) de: to tell (someone) to do
• s'efforcer de: to endeavor to do
• espérer: to hope to do
• essayer de: to try doing
• falloir: to be necessary to do
• hésiter à: to hesitate to do
• interdire (à qqun) de: to forbid (someone) to do
• penser: to be thinking of, to consider doing
• permettre: to allow to do
• persister à: to persist in doing
• promettre: to promise to do
• préférer: to prefer doing
• refuser de: to refuse to do
• risquer de: to risk doing, to possibly do
• souhaiter: to hope to do
• tâcher de: to try doing
• tenter de: to attempt doing
• voir: to see (someone) do, to see (something) done

Word Order with Semi-Auxiliary Verbs 

Semi-auxiliary verbs are used in what I call dual-verb constructions, which have a slightly different word order than compound verb tenses. Dual verb constructions consist of a conjugated semi-auxiliary verb, such as pouvoir, devoir, vouloir, aller, espérer, and promettre, followed by a second verb in the infinitive. The two verbs may or may not be joined by a preposition.

Agreement with Semi-Auxiliary Verbs

In semi-auxiliary verb constructions, any direct object belongs to the infinitive, not the semi-auxiliary verb. Therefore, the past participle never agrees with any direct object. 

It's a decision that I hated to make.
RIGHT: C'est une décision que j'ai détesté prendre.
WRONG: C'est une décision que j'ai détestée prendre.

Here are the books that I wanted to read.
Right: Voici les livres que j'ai voulu lire. 
Wrong: Voici les livres que j'ai voulus lire.

However, there may be other kinds of agreement:

1. With the subject of the sentence, if the auxiliary verb of the semi-auxiliary is être (e.g., Nous sommes venus aider).
2. With the subject of the infinitive.