Dear children, go push open that ancient door and explore a beautiful and unknown world! You see, Hou Yi drew his crossbow and attached a sharp arrow; diseases and disasters flew out of Pandora's box; the snail girl hid behind the door and peeked secretly; the spring of wisdom in the center of the universe gurgled... Let the crystal clear dew of mythology and stories accompany you as you grow, and remain fresh in your memory forever. This book strives to follow the cognitive rules of primary school students, pay attention to the characteristics of primary school students in terms of physiology, psychology and learning methods, and consider the learning ability and cognitive level of primary school students. The content is not only colorful and difficult, but also close to the actual life and thinking of primary school students, and is as close to primary school students as possible. The world of experience and imagination of students can fully mobilize their curiosity and desire for knowledge, and mobilize their enthusiasm for independent learning, so that they can be emotionally influenced, their thoughts inspired, their knowledge expanded, their horizons broadened, and their abilities cultivated in learning that is interesting, novel, and pleasurable.