改为被动语态 1.People often invite me to parties.2.Someone paints the shelf.3.Wewill plant trees

1.I am often invited to parties by people.
2.The shelf is painted by someone.
3.Trees will be planted by us next year.
4.The blackboard has been cleaned by someone.
不明白的再问哟,请及时采纳,多谢!