11. Columbus discovered America.
→America was discovered by Columbus.
12. The police caught the theft.
→The theft was caught by the police.
13. They didn’t look after the children properly.
→The children was not looked after properly
14. They have changed the date of the meeting.
→The date of the meeting have been changed.
15. Tam broke the glass.
→The glass was broken by Tam.
16. Nga left my handbag on the bus this morning.
→My handbag was left by Nga on the bus this morning.
17. People speak English everywhere.
→English is spoken everywhere.
18. You don't prepare your lessons before school.
→Your lessons are not prepare before school.
19. Ba can fix his bike by himself.
→His bike can be fixed by himself.
20. They built the house in 2000.
→The house was built by them in 2000.