Odpowiedź:
1. While I was travelling around the country, my camera was stolen from my hotel room.
While I was travelling around the country, somebody stole my camera from my hotel room.
2. The telephone was invented in the 19th century by Alexander Graham Bell.
Alexander Graham Bell invented the telephone in the 19th century.
3. My class was informed about the test results by our teacher.
Our teacher informed my class about the test results.
4. Jack and Helen were invited to a party by Jack.
Jack invited Jack and Helen to a party.
5. The book wasn't found by Kate.
Kate didn't find the book.