What is the difference between the imperfect and the perfect tense?

Spoken french uses different kinds of tenses to talk about the past. The main two which are used are the imperfect (l'imparfait) and the perfect (le passé composé). The imperfect tense, which is formed with the endings -ais, -ais, -ait, -ions, -iez, -aient, is used to 1) describe what was happening in the past (for example, he was feeling sad : il se sentait triste). 2) to talk about something which used to happen regularly in the past, like a habitual action (le lundi matin, j'allais au cinéma). 3) to talk about something which was happening when something else took place (nous regardions par la fenêtre quand il est arrivé). The perfect tense In comparison to the imperfect, which often describes ongoing states of action, the perfect tense describes action in the past which has been completed. For example, we can say that last week, I went on holiday (la semaine dernière, je suis allé(e) en vacances). The holiday is a completed action and something which is finished, so we use the perfect tense. Remember, when we form the perfect tense, we need to choose the right auxiliary verb (either avoir or être).