This is the 11715th most frequent Russian word.
завершены
"Завершены" means "completed" or "finished" in English.
In this sentence, 'завершены' is used to indicate that the action of completing the project has been carried out in a specific timeframe and is now finished.
Проектные работы завершены.
The project work is completed.
Here, 'была завершена' indicates an action in the past where the process of completing the book was finalized.
Книга была завершена до конца месяца.
The book was completed by the end of the month.
In this context, 'завершены' refers to a required status where all tasks are finished as a condition for another action.