The passive voice

1. People burn wood to heat buildings.
Wood ...............................
2. Last night two statues ....................... (steal) from a museum in the city centre.
3. Iron .......................... (use) to make many things during the Iron Age.
4. The builders have broken the glass window.
The glass window .............................
5. Every day, English exams ......................... (take) by thousands of people around the world.
6. A company called Dupont developed nylon in the 1930s.
Nylon ....................................
7. Someone discovered rubber many years ago in South America.
Rubber ...........................................
8. People will recycle plastic more in the future.
Plastic ..................................
9. Gold ................................... (find) in Wales in 74 AD.
10. Companies make boxes out of cardboard because it's a cheap material.
Boxes ........................... because it's a cheap material.
11. Builders won't use concrete as much in the future.
Concrete ................................
12. In the UK, more money ................................. (spend) on the internet every year.