Change these sentences into passive voice

VII. Change these sentences into passive voice.
1.      A group of students have met their friends at the railway station.
2.      They didn’t allow Tom to take these books home.
3.      The teacher won’t correct exercises tomorrow.
4.      How many trees did they cut down to build that fence?
5.      This well-known library attracts many people.
6.      All students attended the meeting.
7.      People say that he is intelligent.
8.      He can’t repair my bike.
9.      The doctors have operated Tom since 10 o’clock.
10. This is the second time they have written to us about this.