Laila wrote the letters
The letters were written by Laila
by / painted / this / was / wall / students
This wall was painted by students.
bought / my / phone / has / a / friend
My friend has bought a phone.
Ahmed opened the door.
The door was opened by Ahmed.
My mother baked a cake.
A cake was baked by my mother
fixed / car / been / has / the / mechanic / by
The car has been fixed by the mechanic
has / cake / the / eaten / been
The cake has been eaten
Sara cleaned the rooms
The rooms were cleaned by Sara
Someone built the bridge.
The bridge was built