Ответ:

1.Olga will be invited to the party by Oleg.

2.Grammar rules are explained by the teacher.

3.The plan has been accepted by the committee.

4. The toys were being washed by my cousins.

5. The magazine has been returned to the library by Tamara.

6.The document will be signed by the manager.

7. The pencil was sharpened by Sveta.