Pendant, Depuis, Il y a, Pour: durations

English uses for and in to cover an enormous range of duration meanings. I lived there for five years, I have been living there for five years, I'll be there for two weeks, I did it in two hours, I'll be there in an hour — every one of these uses for or in, and every one of them takes a different French preposition. The system is small (six prepositions), tightly organized (each preposition pairs with specific tenses), and exceptionally high-frequency. Once you internalize the matrix below, a whole class of awkward translations becomes natural.

The six prepositions sort themselves cleanly:

The crucial pairings are depuis + present, il y a + passé composé, and en vs dans for in. The rest of this page works through each preposition with examples, then drills the contrasts.

Pendant: completed duration

Pendant (during, for) measures a finished span of time. The action started, ran for X time, and is now over. The natural tense is the passé composé for one-off completed events, or the imparfait for habitual or backgrounded ones.

The first sentence implies you no longer live in Lyon — the five years are closed, in the past. If you still live there, the right preposition is depuis, and the tense changes from passé composé to présent.

In casual speech, pendant is often dropped entirely with a duration noun:

This is normal — duration nouns can stand on their own as adverbials. But you cannot drop pendant in front of a definite event noun (pendant la guerre, pendant les vacances — the pendant is required there).

Depuis: ongoing duration with the present tense

Depuis covers two related meanings — since (a starting point) and for (a duration that started in the past and is still going). Both meanings pair with the present tense when the action is ongoing now.

This is the single biggest tense-and-preposition conflict between English and French. English uses the present perfect (I have been living) for an ongoing situation; French uses the simple present (j'habite). The reasoning is that the action is happening now — and French marks that with the present tense, regardless of when it started. Depuis alone carries the since/for meaning.

When the ongoing situation is being described from a past viewpoint — I had been living there for five years when X happened — the tense shifts from present to imparfait, but the logic is the same: depuis + the tense that describes the action as ongoing at the reference time.

Il y a: ago

Il y a (literally there is) when followed by a duration means ago. It locates a single past event at a distance from now. The natural tense for the main verb is the passé composé.

Note the position: il y a + duration usually goes at the end of the clause in everyday speech, mirroring English X ago. Front-loaded il y a deux ans, on s'est rencontrés is also possible — slightly more emphatic.

A subtle but useful distinction: il y a points to a completed past event; depuis points to an ongoing situation that started at that point. Compare:

Both refer to the same ten-year span, but the first one is about a single past starting point, and the second is about the ongoing state.

Pour: planned future duration

Pour expresses a planned or intended duration — typically a stay, a trip, or a commitment. It is forward-looking, not retrospective.

The key word is planned. Pour deux semaines is a planned span — you intend to be there for two weeks. If you were there for two weeks and now you have come back, the right preposition is pendant: je suis allé à Berlin pendant deux semaines (completed past). If you have been there for two weeks and you are still there, depuis: je suis à Berlin depuis deux semaines.

This pour is restricted in scope — it occurs mostly with verbs of motion (partir, aller, venir) and stay (être quelque part). For other completed durations, French uses pendant, not pour.

Dans: in (a future interval)

Dans + duration locates an action after a future interval — exactly equivalent to English in in I'll see you in an hour.

The action happens at the end of the named interval — five minutes from now, in half an hour, two weeks from today.

En: in (within a span)

En + duration means within that span — the duration of an action, measured from start to finish.

This is the duration of doing — how long it took to complete an action. English in covers both en (within a span) and dans (after an interval), so this is one of the trickiest contrasts for English speakers.

The clean test:

• I'll be there in an hour. (after an interval of waiting) → Je serai là dans une heure.
• I read it in an hour. (the reading itself took one hour) → Je l'ai lu en une heure.

These two sentences look almost identical in English but mean opposite things: dans counts forward from now, en measures the span of doing.

Comparison drill

The same English duration can map to four different French prepositions depending on context. Here is the drill.

I lived there for five years (completed past).

I have been living there for five years (ongoing).

I'll be there for five years (planned future stay).

I built it in five years (action took that span).

I'll start in five years (after an interval).

I finished it five years ago (completed past, distance from now).

The same noun phrase — cinq ans — combines with six different prepositions to express six different temporal relations. There is no shortcut: each pairing must become automatic.

Depuis quand vs depuis combien de temps

Two question forms cover the depuis domain. Depuis quand asks for a starting point; depuis combien de temps asks for a duration.

The expected answers reuse the same preposition: depuis 2018 / depuis trois ans. Both questions take the present tense in the verb — the same rule applies.

Common Mistakes

These six errors cover most of the duration-preposition mistakes English speakers make. The single most damaging is the depuis + passé composé error — it actively misleads the listener, who hears a closed past action where you mean an ongoing one.

Key takeaways

• Pendant
  • passé composé/imparfait = completed duration (j'ai habité là pendant cinq ans).
• Depuis
  • present = ongoing duration (j'habite ici depuis cinq ans). With imparfait when seen from a past reference point.
• Il y a
  • passé composé = ago (je l'ai vu il y a une heure).
• Pour
  • duration = planned future stay (je pars pour deux semaines). Restricted to motion/stay verbs.
• Dans
  • duration = after a future interval (dans cinq minutes). The action begins at the end of the interval.
• En
  • duration = within a span — how long the action takes (je l'ai fait en deux heures).
• The pairings are tight: depuis
  • present and il y a
    • passé composé are the two most-tested. Remember that French uses the present tense for ongoing situations where English uses the present perfect.