Chuyển các câu sau sang câu bị động: 1. They sent millions of Christmas cards last month 2. The Greens often take her to the theatre 3. I must finish this test on time 4. They have just built a new bridge 5. They have known him well 6. This boy broke my window yesterday 7. People plant ricein tthose fields 8. He is asking the police questions 9. Did you do your test perfectly 10. No one could help her