Every year the curriculum focuses on one of the standard works of the Church; the Old Testament, the New Testament, the Book of Mormon, and the Doctrine and Covenants. Students attend seminary for four years, so that they are able to learn about all four books of scripture in-depth. Students are also asked to memorize twenty-five selected scriptures, known as Scripture Mastery verses, from the book of scripture being studied that year. Over the course of four years, a seminary student has had the opportunity to memorize 100 scripture verses. (Click on this link to learn more about Scripture Mastery verses.) The classes are free, and the Church Educational System provides manuals and student materials, except for scriptures.