Passive
Let’s talk about passive voice!
In English, to emphasize what is done, instead of who did it, we can say things like the books are used. In French, you say les livres sont utilisés.
Ces livres sont utilisés par mes élèves.
To talk about the past and say something like the book was sold, use être in the passé composé.
Notice that the verb after être changes to match the gender and number of the noun it refers to.