在双语课堂中，教师不仅是学生语言输入最重要的来源，也是学生以目的语进行

In a bilingual classroom, teachers are not only the most important source of students' language input, but also planners, instructors, and participants of meaningful interactions with the target language. The media language can play the role of teaching aid and communication channel in this process. In a broad sense, the medium of instruction refers to all "the language used by teachers in classroom teaching." According to this definition, it can be divided into two categories: "single use of the target language" and "mixed use of the target language with other languages".

In bilingual classrooms, teachers are not only the most important source of language input for students, but also planners, mentors and participants for meaningful interaction in the language of purpose. Media language can play the role of teaching aids and communication channels in this process. The broad medium of instruction refers to all the languages used by teachers to teach in the classroom. According to this definition, it can be divided into "single-use destination language" and "purpose language mixed with other languages" two categories.

In bilingual classroom, teachers are not only the most important source of students' language input, but also the planner, instructor and participant of students' meaningful interaction in the target language. And media language can play a role of teaching assistance and communication channel in this process. In a broad sense, teaching medium language refers to all the "language used by teachers in classroom teaching." According to this definition, it can be divided into two categories: "target language alone" and "target language mixed with other languages".<br>