Abstract: The flipped classroom model is a new teaching mode, the essence of which lies in the flipped teaching of teachers' knowledge and students' knowledge internalization. It can enhance the teaching effect by exerting students' subjective initiative. There are three dilemmas in the process of integrating flipped classroom model into classroom teaching, the difficulty of changing the way of knowledge imparting, internalizing the independent absorption of knowledge, and controlling the reasonable use of time. It requires teachers to continuously optimize the guidance before class, actively carry out effective teaching and strengthen the consolidation after class, so as to achieve the purpose of improving the pertinence and effectiveness of teaching.

Key words: Flipped classroom model, Dilemmas, Strategy, Learning efficiency