China is setting off a 3D. printing investment boom. Facing the broad prospects of 3D. printing, 3D. printing industrial parks have been established in various places and various preferential policies have been introduced. But the development of 3D. printing as an emerging technology is not enough with enthusiasm In the 3D printing industry chain, the constraints of key technologies, materials, and software need to be broken through.3D. Printing technology is still in its infancy. If enterprises and capital inflow in large quantities, it will not produce benefits in a short time. The text is intended to explain:. ['D. The application scope of printing needs to be fully explored.', 'D. The development of printing technology encountered a bottleneck.', 'Policies should be introduced to encourage 3D. Development of printing technology.', 'Funds should not be poured into 3D blindly. Printing.']