Chuyển sang bị động: 1. Can you see Lan use my pen? ………………………………………………………………………………………... 2. It is easy for him to study Mathematic. ………………………………………………………………………………………... 3. Is it dangerous for them to cut off the trees? ………………………………………………………………………………………... 4. It can be useful for you to use English fluently. ………………………………………………………………………………………... 5. You need to have your hair cut ………………………………………………………………………………………... 6. He doesn’t need to keep his bag all the time. ………………………………………………………………………………………... 7. Do you need to open the windows?. ………………………………………………………………………………………... 8. He wants someone to solve this problem. ……………………………………………………………………………………….. 9. I want you to remember these difficult cases. ………………………………………………………………………………………...