chuyển câu bị động sang câu chủ động 11. All the arrangements have been made. 12. When was this radio manufactured? 13. They couldn’t be found anywhere. 14. Is mathematics taught in this school? 15. Fortunately the machinery wasn’t damaged by the accident. 16. Please wait here while your luggage is being examined. 17. How are candles made? 18. For a long time the earth was believed to be flat. 19. Were you taught how to apply this theory by your teacher? 20. Apples are said to be good for our health. 21. Don’t let the dog be teased by the children. 22. It is believed that red is the symbol of luck. 23. What have been done to help the poor in this city? 24. The jewelry must have been stolen while she was out. 25. Where did the treasure use to be hidden by pirates in the old time?