In English, the perfect tense always requires the auxiliary verb "to have", but in French, you will need to use either avoir (= "to have") or "être" (= to be). Most verbs will require "avoir". The minority of verbs requiring "être" are summed up in the mnemotechnic device "MRS. VAN DER TRAMP", which stands for:- Monter- Rester- Sortir - Venir- Aller- Naitre - Descendre- Entrer- Rentrer - Tomber- Retourner- Arriver- Mourir- Partir All derivatives of these verbs (e.g. revenir, devenir) will also need "être". Finally, all reflexive verbs will need "être".