Complex sentence: A Blab school was a type of school common in United States in the 19th century where books and materials were uncommon, and lessons consisted of a teacher speaking a lesson, and the students reciting it back.
Split into simpler sentences: A Blab school was a type of school common in United States in the 19th century. Typical of schools of the nineteenth century was where books and materials were uncommon, and lessons consisted of a teacher speaking a lesson, and the schoolchildren reciting it back.