Ex.21.Change the active sentences into passive sentences. Use the words in brackets.
Exemple: We sell tickets for all shows at the box office. (Tickets for all shows/sell/at the box office)
Tickets for all shows are sold at the box office.
1. Thomas Edison invented the electric light bulb. (The electric light bulb/invent/by Thomas Edison)
2. Someone will paint the office next week. (The office/paint/next week)
3. Several people saw the accident. (The accident/see/by several people)
4. Where do they make these computers? (Where/ these computers /make)
5. A stranger helped me. (I/help/by a stranger)
6. They don't deliver the post on Sundays. (The post/not/deliver/on Sundays)

1. Thomas Edison invented the electric light bulb. (The electric light bulb was invented by Thomas Edison)

2. Someone will paint the office next week. (The office will be painted next week)

3. Several people saw the accident. (The accident was seen  by several people)

4. Where do they make these computers? (Where are these computers made?)

5. A stranger helped me. (I was helped by a stranger)

6. They don't deliver the post on Sundays. (The post is not delivered on Sundays)