depuis

In a sentence

• J'habite ici depuis cinq ans.

  I have been living here for five years.

  In this sentence, 'depuis' is used to indicate the duration of an action that started in the past and continues in the present.

• Depuis son départ, la maison semble vide.

  Since his departure, the house feels empty.

  Here, 'depuis' establishes a point of time from which an ongoing state or condition began.

• Depuis quand aimez-vous le jazz ?

  Since when have you liked jazz?

  This use of 'depuis' inquires about the starting point in time of a preference that persists until now.