How do I know when to use être or avoir as an auxiliary verb?

An auxiliary verb is the first verb used in a compound tense (when more than one verb is present) such as le passé composé.

Most French verbs take the auxiliary verb avoir - J'ai regardé la télé.

However, there are certain cases where the verb être is used as the auxiliary verb.

 

Verbs to do with movement (MR VANS TRAMPED):

                  INFINITIF             PARTICIPE PASSÉ

M mourir    (to die)                Mort

R rester     (to stay)              Resté

V venir       (to come)            Venu

A aller        (to go)                 Allé

N naitre      (to be born)        Né

S sortir       (to go out)           Sorti

T tomber    (to fall)                Tombé

R retourner         (to return)           Retourné

A arriver     (to arrive)            Arrivé

M monter   (to climb)             Monté

P partir       (to leave)            Parti

E entrer     (to enter)            Entré

D descendre(to go down)     Descendu

 

The verbs above are to do with some sort of movement, so use être when dealing with these verbs.

 

Remember: the verb être makes the past participle (allé, arrivé, mort) work like an adjective. Therefore the past participle must agree with who did the action.

Add –e if it’s feminine Elle est arrivée trop tard.

Add –s if it’s masculine plural Ils sont montés la montagne.

Add –es if it’s feminine plural. Les trois filles sont parties tôt