| Lesson Study (LS) is a process in which teachers and teacher educators work collaboratively to improve the quality of classroom practice through cycles of lesson planning, teaching and reflection. As an effective mode of teacher-led professional development, LS is now being promoted internationally.This study mainly explores the subtle changes that LS brought to novice teachers' professional learning by applying LS to infinitives' instruction. The primary research questions are as follows:1) what teaching achievements did the novice teachers make through LS? 2) what changes have occurred to novice teachers' pedagogical content knowledge (PCK) about grammar teaching and their perception of the learning community? 3) What's the role of the university supervisor and the school mentor teachers in the LS? Among the three questions, the second one is the main focus of this study. The present study mainly employs the action research method and investigation research method. That is, three novice teachers formed a LS research group and went through three rounds of circular process of collaboratively making teaching plan, conducting and reflecting on research lesson. The research data were mainly collected from pre-test and post-test to students, novice teachers'reflective journals, audio-recording of group meetings, video-recording of research lessons, field notes made by novice teachers and mentor teachers, questionnaires and interviews to the novice teachers and their students, as well as emails from the university supervisor.The main findings are as follows:LS has brought positive effect on students' knowledge of infinitives, communicative competence and attitudes and beliefs; LS has increased novice teachers' professional content knowledge in terms of students, curriculum, pedagogy and themselves; LS has changed novice teachers' perception of the learning community through being exposed to many knowledge co-constructing opportunities in communication, observation and reflection; the university supervisor and school mentor teachers played a role as facilitator and helper in novice teachers' LS implementation process. Their scaffolding, support and help provided on some key occasions were very crucial in the LS. |