1. The Basic Rule: Use "Avoir" for Most Verbs
The vast majority of French verbs use "avoir" as their auxiliary verb in the passé composé. Examples:
* J'ai mangé (I ate)
* Elle a dormi (She slept)
* Nous avons chanté (We sang)
2. Verbs That Use "Être"
A specific group of verbs, known as verbs of movement or change of state, use "être" as their auxiliary verb. Here's a way to remember them:
* D.R.M.P.S. - "Devenir, Rester, Mourir, Paraître, Sortir"
* Devenir (to become)
* Rester (to stay)
* Mourir (to die)
* Paraître (to appear)
* Sortir (to go out)
* Additional Verbs that use Être:
* Aller (to go)
* Arriver (to arrive)
* Entrer (to enter)
* Monter (to go up)
* Descendre (to go down)
* Naître (to be born)
* Revenir (to come back)
* Tomber (to fall)
* Venir (to come)
3. Agreement in the Past Tense
When using "être" as the auxiliary verb, the past participle (the "-ed" form in English) must agree in gender and number with the subject of the verb.
Example:
* Elle est sortie. (She went out) - "sortie" is feminine singular to agree with "elle"
* Ils sont venus. (They came) - "venus" is masculine plural to agree with "ils"
4. Important Note:
* Reflexive Verbs: All reflexive verbs (verbs with "se") always use "être" as their auxiliary verb, and the past participle must agree with the subject.
* Je me suis lavé. (I washed myself)
Let me know if you'd like more examples or have any other questions!