The traditional three-dimensional structure composed of teachers, students and courses will be transformed into a new four-dimensional structure, namely students, digital learning environment, digital learning resources and teaching support services. Teachers will become supporters and servers of students' learning activities based on digital environment and resources. ? Just as the report "American Teaching 2030" puts forward the idea of future teaching work: with the change of teaching ecology, especially the application of cognitive science, teachers and students will be encouraged to conduct immersive personalized learning, and the mixed learning environment (combining face-to-face and online learning) will seamlessly integrate teachers, students, families, local and remote professionals, volunteers and business people, making the school a learning center of the whole community. Therefore, teachers will play more diverse roles, including learning tutors, personal education consultants, community think tank planners, education inspectors, social and humanistic platform developers, evaluation designers and so on. ?