把下面的主动语态改为被动语态(在线等!)
把下面的主动语态改为被动语态(在线等!)
1.He wrote a poem.
2.The students are planting some trees and flowers.
3.They are to open up a new business next week.
4.Children couldn't have done all this damage.
5.All of us will see him off at the airport.
6.They feed the tigers at the zoo three times a day.
7.You must hand in your homework before five.
8.People say that she is a good teacher.