As in English, the passive voice in French is composed of a tense of the verb to be and a past participle. Any transitive verb with a direct object can be made passive. The active form, le chat mange la souris is made passive thus: La souris est mangée par le chat.
The subject in the active sentence (le chat) becomes the object of the passive. The object of the active (la souris) becomes the subject of the passive sentence preceded by "par." The verb of the active sentence is changed into a past participle (mange becomes mangée, notice the agreement!) preceded by a form of être.
Elle est portée par Jean. She is carried by John.
Elles ont été inspirées par Van Gogh. They were inspired by Van Gogh.
Il avait été tué par les soldats français. He had been killed by French soldiers.
If a verb takes an indirect object, it cannot be transformed into the passive voice. In this case, on is used in the active construction.
On a donné un cadeau à ma mère. My mother was given a present.
On lui a dit de retrouver le collectioneur au musée. He was told to meet the collector at the museum.
Notice how pronominal verbs change from active to passive:
Active: Je me suis réveillée. I woke up.
Passive: J'ai été réveillée par quelque chose. I was awakened by something.
Depuis, il y a, and pendant in past contexts
1. To express an action that has been going on, depuis (or il y a ... que) is used with the present tense.
Depuis quand avez-vous votre ordinateur?
Depuis combien de temps avez-vous votre ordinateur?
How long have you had your computer? |
Je l'ai depuis deux ans.
Ça fait deux ans que je l'ai.
Il y a deux ans que je l'ai.
I've had it for two years. |
| Je conduis depuis longtemps. |
I have been driving for a long time. |
2. But to express an action that had been going on for some time when something else happened,
depuis is used with the imperfect.
Nous conduisions depuis deux heures,
quand j'ai proposé de prendre le volant. |
We had been driving for two hours
when I volunteered to drive. |
3. To express an action that you have not done for some time, use depuis with the passé composé.
| Je n'ai pas conduit depuis mon mariage. |
I haven't driven since I've been married. |
4. To express an action that was done for a period of time, pendant is used, usually with the passé composé. But for an action that was completed some time ago, use il y a, also with the passé composé.
| J'ai loué une voiture pendant une semaine. |
I rented a car for two weeks. |
| J'ai appris à conduire il y a deux ans. |
I learned to drive two years ago. |
French - Forms of Tout, Passive Voice, Depuis, il y a, and pendant in past contexts 
