Chuyển những câu sau sang câu bị động: 1. Someone can pick them up at the hotel. 2. You must always keep your room tidy & clean. 3. People shouldn't sell food on the sidewalks. 4. Someone ought to repair this window. 5. Someone should deliver the message soon. 6. The children must wear uniform to school. 7. They are going to build a new workshop in school.| 8. He could play chess when he was young. 9. You may use this room for the meeting place. 10. They can't make tea with cold water.