What are the comprehensive prediction functions of tortoise shell?

Tortoise shells are used in Oracle Bone Inscriptions, and so are the bones of other animals. Some people think that animal bones are used because there are no tortoise bones. That was not the case. In the remains of Longshan culture and Qijia culture in the Central Plains, many Oracle bones are made of the shoulder blades of cattle, deer, pigs and sheep. Look carefully, it is a relatively simple bone for divination. If it is more complicated and grand, it is necessary to use tortoise shells, as Mr. Mou said in the book Origin of Ancient Chinese Characters in China: "Divination with the shoulder bones of cattle cannot replace tortoise shells. Bone divination is a single divination method, instead of using the shoulder blades of cattle or other animal bones without tortoise shells. Tortoise shell has the function of comprehensive prediction, that is, it can pray, ask, predict and display. "