`1.`The bicycle was bought by her last year.
- Bị động thì QKD
- S + was/were + VpII + (by + O)
`2.` Some letters are being written by them.
- Bị động thì HTTD
- S + am/is/are + being + VpII + (by + O)
`3.` The dishes will have been washed by my sister by 8 p.m.
- Bị động thì TLHT
- S + will + have + been + VpII + (by + O)
`4.` The exercise had been done by the pupils.
- Bị động thì QKHT
- S + had + been + VpII + (by + O)
`5.` The floor was cleaned by the children yesterday
- Bị động thì QKD
- S + was/were + VpII + (by + O)