They have not read the book.

1. The book had not been read by them.
2. The book was not read by them.
3. The book has not been read by them.
4. The book is not being read by them.

Converting present perfect negative active to passive maintains tense and negation. Original: “They have not read.” Passive: “The book has not been read by them.” Structure: subject (book) + has + not + been + past participle (read). The negative “not” remains after the auxiliary. Present perfect passive negative indicates that reading has not occurred up to the present, emphasizing the book’s unread status.