1.The project hasn't been finished by my sister yet.

    2. You will be sent a letter of invitation (by them) soon.

    3. A lot of food had bought (by them).

    4. The bill won't be paid by Jack.

    5. His new collection is going to be introduced by him this evening.

    6. The correct answer can't be found out.

    7. My car was be repaired by the mechanic.

    8. Natural resources must be saved for future use (by us).

    9. Clothes have to be washed by Mai every day. 

   10. Her motorbike has been stolen.

   11. No books are left on the table.

   12. French and English are spoken in Canada (by people).