Imparfait vs passé composé

This is the decision English speakers get wrong most often in French, and it is not because the rules are complicated. It is because English does not make the distinction. “I worked” can be a habit, a background or a single event, and English leaves it to context - French makes you choose.

The short version

The imparfait describes. The passé composé reports.

Il pleuvait - it was raining (the situation) Il a plu - it rained (an event that happened)

Neither is more past than the other. They are two ways of viewing the same stretch of time.

Three tests that decide it

Is it a line or a point? An action with duration, no clear start or end, is a line - imparfait. An action you could put on a timeline as a single dot is a point - passé composé.

Could you say “used to” or “was …-ing”? If either fits the English, you want the imparfait. I used to take the train and I was taking the train are both je prenais le train.

Does the story move forward? Passé composé advances the narrative; imparfait pauses it to look around. In any paragraph of French past narration, the events are in the passé composé and the scenery is in the imparfait.

The classic pairing

The two tenses very often appear in one sentence, with the imparfait interrupted by the passé composé:

Je mangeais quand il a téléphoné. - I was eating when he called. Il faisait nuit quand nous sommes arrivés. - It was dark when we arrived. Elle lisait pendant que je préparais le dîner. - both ongoing, so both imparfait.

That last one shows the pattern is not automatic. Two simultaneous ongoing actions both take the imparfait; it is the interruption that calls for the passé composé, not the second verb.

The verbs that change meaning

With verbs describing states, the choice of tense changes what the sentence means - not just how it feels. These are worth learning as pairs:

Verb	Imparfait	Passé composé
savoir	je savais - I knew	j’ai su - I found out
pouvoir	je pouvais - I was able to	j’ai pu - I managed to
vouloir	je voulais - I wanted	j’ai voulu - I decided to / I tried to
devoir	je devais - I was supposed to	j’ai dû - I had to / I must have
connaître	je connaissais - I knew (someone)	j’ai connu - I met
avoir	j’avais peur - I was afraid	j’ai eu peur - I got a fright

The pattern is consistent: the imparfait gives the ongoing state, the passé composé gives the moment it started or the action it produced.

Signals worth noticing

Certain time expressions habitually travel with one tense or the other. They are hints, not laws - but if you find yourself writing tous les jours next to a passé composé, check it.

Pulls towards the imparfait	Pulls towards the passé composé
souvent, toujours, d’habitude	soudain, tout à coup
tous les jours, le lundi	hier, lundi dernier, un jour
pendant que, comme	une fois, deux fois, puis

Common mistakes

Common questions

Is there a rule that always works?

No single rule, but a reliable question: are you describing the situation or reporting an event? Descriptions, states and habits take the imparfait; single completed events take the passé composé. Most sentences that feel genuinely ambiguous are ones where either is correct and the choice changes the emphasis.

Can both appear in the same sentence?

Constantly - it’s the normal shape of French past narration. Je mangeais quand il a téléphoné. The imparfait is the ongoing situation, the passé composé is the event that interrupts it.

Do time expressions decide it?

They’re a strong hint, not a rule. Souvent, tous les jours, le lundi, toujours pull towards the imparfait; hier, soudain, une fois, lundi dernier pull towards the passé composé. Treat them as evidence rather than instructions.

Why do some verbs seem to change meaning?

Because with a state verb, the two tenses describe genuinely different things. Je savais is “I knew” (an ongoing state); j’ai su is “I found out” (the moment it began). Same verb, different aspect.