1. This film has been seen before.
2. The newspaper has been read already.
3. These movies have been seen yet.
4. The contract has been signed.
5. The tickets have been bought by these men.
6. The English grammar has been explained by our teachers.
7. The pollution has been discussed since last week.
8. Has the lost valuable painting be stolen in the national museum ?
9. Have the above sentences been finished ?
10. This room has been cleaned by Lan.
11. Their homework have been done.
12. This film has been seen three times by Lan.