A: ① In education, the research process and results should actively promote the physical and mental development of preschool children; (2) Practicality, research topics and achievements can provide rich information for educational decision-making departments or preschool children's workers; (3) Feasibility: When considering the bearing capacity of personnel, funds, equipment, technology and other conditions, we should choose the subject scope realistically; (4) Appropriateness, selecting or compiling the test according to the characteristics of the research object; ⑤ Accuracy, the research process should be carried out in accordance with the established scheme, methods and procedures, and shall not be changed at will.