"Je vais à Paris depuis une semaine." Can you spot the problem? With "depuis", you describe something that's still going on. But "je vais à Paris" is a one-time trip - you can't be in the process of going to Paris for an entire week. These three little words - depuis, pendant, il y a - are among the most confused in French. And yet the logic is simple.
"Depuis" indicates an action that started in the past and is still going on now: "j'habite ici depuis 5 ans" (I have been living here for 5 years - and I still do). "Pendant" indicates a limited duration, often completed: "j'ai habité là pendant 5 ans" (I lived there for 5 years - it's over). "Il y a" means "ago" and goes before a duration: "il y a 3 ans" (3 years ago). These three expressions answer different questions: since when? for how long? when in the past?
Depuis - It's Still Going On
This is the key. "Depuis" is used when the action or state started in the past and is still happening at the moment you speak. In French, you use the present tense (not the past) with "depuis".
- "J'habite à Lyon depuis 2019." (and I still live there)
- "Elle apprend le français depuis trois mois." (and she's still learning)
- "On se connaît depuis l'université." (and we still know each other)
This is a massive trap for English speakers. In English, you say "I have been living here for 5 years" with a present perfect continuous. In French, it's the simple present tense: "j'habite ici depuis 5 ans".
Here's a real mistake I see regularly:
- ❌ "Il y a des années, j'ai habité au Texas depuis"
✅ "Il y a des années, j'habitais au Texas" or "J'habite au Texas depuis des années"
Here, the student mixed "il y a" and "depuis" in the same sentence, creating a short circuit. Either you're telling something that's over (passé composé + il y a), or you're talking about something still going on (present + depuis). Not both at the same time.
Pendant - A Duration, A Frame
"Pendant" answers the question "for how long?". It's a defined duration - often in the past, but also in the future.
- "J'ai vécu à Bordeaux pendant deux ans." (it's over, I no longer live there)
- "On va partir en vacances pendant trois semaines." (planned duration)
- "Il a plu pendant toute la journée." (from morning to evening, done)
Here's the classic mistake:
- ❌ "Je vais à Paris depuis une semaine"
✅ "Je vais à Paris pendant une semaine"
In this case, you're planning a one-week stay. It's a defined duration, not an ongoing state from the past. You need "pendant".
Il y a - In the Past
"Il y a" + a duration = "ago" in English. That's it. It places an event in the past, at a certain distance from the present moment.
- "J'ai déménagé il y a six mois." (six months ago)
- "On s'est rencontrés il y a dix ans." (ten years ago)
- "Il y a trois jours, j'ai reçu un mail bizarre." (three days ago)
Watch out for the classic trap: in French, you say "il y a 8 ans", not "8 ans avant" when speaking relative to now.
- ❌ "C'était 8 ans avant"
✅ "C'était il y a 8 ans"
"Avant" exists in French, but it's used relative to another event in the narrative, not relative to now. "Il a déménagé deux ans avant son mariage" - that's correct because you're comparing two past events.
The Ans / Années Trap With "Il y a"
This is a subtlety many people miss. With "il y a", you always use "ans" (a dry unit of measurement), never "années" (lived duration).
- ❌ "Sauf un petit voyage il y a 30 années"
✅ "Sauf un petit voyage il y a 30 ans"
On the other hand, "années" is used with "pendant", "depuis", or "quelques" because the emphasis is on the lived experience:
- "Pendant plusieurs années, j'ai travaillé à l'étranger."
- "Depuis quelques années, il fait du yoga."
But be careful - "quelques ans" doesn't exist:
- ❌ "Ils doivent passer quelques ans"
✅ "Ils doivent passer quelques années"
Remember: "il y a" + ans. "Pendant / depuis / quelques" + années.
Depuis + Negation = Watch the Tense
With "depuis" in the negative, you can use the passé composé. Why? Because the action is no longer happening - it's the absence that's ongoing.
- "Je n'ai pas mangé depuis ce matin." (the absence of meals has lasted since this morning)
- "Il n'a pas plu depuis trois semaines." (the absence of rain is ongoing)
Compare with the positive form: "Il pleut depuis ce matin." (present tense, because the rain is still going)
Other Common Traps
"Depuis longtemps" with the right verb tense
When using "depuis longtemps", the verb must reflect a state that's still going on:
- ❌ "Un problème qu'elle se batte depuis longtemps"
✅ "Un problème contre lequel elle se bat depuis longtemps"
The subjunctive "se batte" has no business being here. With "depuis", it's the present indicative: "elle se bat". The fight is still ongoing.
"Temps" vs "moment" vs "fois"
In English, "time" can mean everything. In French, it's more precise:
- ❌ "Elle est autorisée à obtenir le passeport à n'importe quel temps"
✅ "... à n'importe quel moment"
"Le temps" = the abstract concept or the weather. "Le moment" = a specific instant (at any time = à n'importe quel moment). "La fois" = an occurrence (three times = trois fois).
The 3-Question Summary
When you're unsure which of these three expressions to use, ask yourself the right question:
- "Is it still true now?" → depuis + present tense. "J'habite ici depuis 2019."
- "How long did it last?" → pendant + duration. "J'ai habité là pendant 3 ans."
- "When was it?" → il y a + duration. "J'ai déménagé il y a 3 ans."
NB: a good test when you're torn between "depuis" and "pendant" - look at the verb tense. If it's the present, it's probably "depuis" (the action is still going on). If it's the passé composé, it's probably "pendant" (the action is over). And with "il y a", make sure you're using "ans" (not "années") when counting years back in time.
