1- This house is haunted by a ghost.
by a ghost : le complément d’agent.
2- He was followed by two policemen.
by two policemen : le complément d’agent
3- This bridge was built by the Romans a long time ago.
by the Romans : le complément d’agent
4- All these books have been written by my friend.
by my friend : le complément d’agent.
5- America was discovered by C.Columbus in 1492.
by C.Columbus : le complément d’agent
6- He was killed by the Germans during the war.
by the Germans : le complément d’agent.
7- It will be posted by my uncle next
by my uncle : le complément d’agent
8- This film is directed by a French producer.
by a French producer : le complément d’agent
voilaaaa!!!!