1. My aunt wrote that book.
That book  is wrote by my aunt.
2. Picasso painted 'Guernica'.
→'Guernica'  was painted by Picasso.
3. The hero saved the city.
The city  is saved by the hero.
4. The thief stole all the paintings.
All the paintings  were stolen by the thief.
5. They built the castles in 1219.
The castles  were built in 1219.
6. The Queen opened the exhibition.
The exhibition was opened by the Queen.
7. They made their instruments out of recycled material.
Their instruments are made out of recycled material.
8. My aunt and uncle organised our summer holiday.
Our summer holiday was organized by my aunt and uncle.