The book is bought by Sara.
1. The books are being bought by Sara. Present Continuous Passive
2. The books have been bought by Sara. Present Perfect Passive
3. The books were bought by Sara. Past Simple Passive
4. The books had been bought by Sara. Past Perfect Passive
5. The books were being bought by Sara. Past Continuous Passive
6. The books will be bought by Sara. Future Simple Passive
7. The books will have been bought by Sara. Future Perfect Passive