Printed literature, machine-readable literature, etc. According to the knowledge of preschool education and the form of literature carrier, preschool education literature can be divided into three types, namely, printed literature, machine-readable literature and microform literature. Preschool education, also known as preschool education, refers to the planned education of children before they enter primary school by institutions that implement preschool education according to certain training objectives and children's physical and mental characteristics.