The French prepositions depuis, pendant, and—far less commonly—pour each express the duration of an event a little differently, with the result that many English speakers mix up depuis and pendant and overuse pour. This lesson explains the different meanings and uses for each preposition.
Depuis means "since" or "for." It is used with a French verb in the present tense to talk about an action that began in the past and continues in the
present. In English, this is indicated by the present perfect or present perfect progressive.
Depuis quand étudiez-vous le français ?
How long have you studied French?
J'étudie le français depuis 3 ans.
I've studied French for 3 years (and still do).
J'étudie le français depuis 2009.
I've been studying French since 2009.
Depuis can also indicate something that was occurring in the past when it was interrupted by some other action. In French, this is stated with the imparfait plus passé composé; in English, the past perfect progressive plus simple past.
Depuis combien de temps dormais-tu quand je suis arrivé ?
How long had you been sleeping when I arrived?
Il vivait en France depuis 2 ans quand je l'ai vu.
He'd been living in France for two years when I saw him.
Pendant means "for" and refers to the entire duration of an
action in the past or future, with no relation to the present.
Pendant combien de temps avez-vous étudié le français ?
How long did you study French?
J'ai étudié le français pendant 3 ans.
I studied French for 3 years (and then stopped).
Je vais habiter en France pendant 2 mois.
I'm going to live in France for 2 months.
Pendant followed by a noun means "during." In this sense, it is synonymous with durant.
J'ai vu un film pendant mon séjour.
I saw a film during my stay.
Pendant ce temps, il m'attendait.
During this time, he waited for me.
Pour can express the duration of an event only in the future. Note that pendant could also be used in all of these.
Je vais y habiter pour 2 mois.
I'm going to live there for 2 months.
Il étudiera en Europe pour 3 ans.
He'll study in Europe for 3 years.
Le projet est suspendu pour un an.
The project is suspended for a year.
Although the verb in the final example is not in the future, the use of pour indicates that the one-year
suspension is either about to start or is currently underway. If the suspension had already occurred, you would have
to use pendant:
Le projet a été suspendu pendant un an.
The project was suspended for a year.