教师话语，一般定义为课堂教学中教师所使用的话语。国内外对教师话语的研究已经有很长的历史。最早的研究主要关注课堂教师话语的数量。随着对语言学习和语言教学的进一步理解，研究者更加关注教师话语的质量，并发现其与学生的学习机会密切相关。与学习机会相关的研究可追溯至二十世纪六十年代。广义的学习机会包括获得输入的机会、交流对话的机会、输出机会、获得反馈的机会等。本研究将学习机会定义为学生参与课堂对话、协商意义、运用目的语进行口头产出以及在低焦虑环境下进行交流的机会。以Wash为代表的研究者们在课堂师生对话中发现了一些能促进学习机会生成的教师话语特征。然而目前国内还缺乏关于教师话语如何影响学生学习机会的实证研究。 本文旨在研究高中英语课堂师生对话中学习机会的现状，找出可能创造或阻碍学习机会的教师话语，并挖掘背后原因。基于学习是一种动态社会行为的理论，本研究认为课堂师生对话类似于真实的日常交流。本研究采用个案研究方法，研究对象为朝阳区三位高中英语教师。研究者分别录制了每位教师的四节研究课，邀请教师和学生对有关片段进行刺激性回想，并对每位教师进行了两次访谈。研究者对所有的视频和音频数据进行细致转录，并运用会话分析方法对研究课进行数据分析。研究发现：第一，英语课堂学习机会的现状差强人意；第二，恰当的教师话语能促进学习机会的产生，如基于内容的反馈、适当的鼓励等；一些教师话语则可能阻碍潜在的学习机会，如打断学生、过多使用母语等；第三，影响教师话语的两个主要因素为教师信念和语言能力。 基于以上发现，本研究认为教师应该增强话语意识并加强对课堂动态性质的认识，以做出关于话语使用的正确决策。此外，教师应加强话语知识和学习机会的理论学习。学校和教师教育项目应向教师输送前沿的教学理念，鼓励教师做行动研究以加深对自身话语使用状况的理解，提升话语策略，创造更多学习机会。本研究仍有一些不足，例如三位教师授课内容和话题不尽相同，这可能成为影响学习机会的外部因素。 总体上，本研究对英语课堂教学实践和教师教育具有应用价值和启示意义。

Teacher talk, which refers to the language used by teachers in classroom teaching, has been the focus of research for a long time both at home and abroad. Early studies mainly focus on the quantity of teacher talk. With the deeper understanding of language learning and teaching, increasing importance has been attached to the quality of teacher talk for it is closely connected with students’ learning opportunities, which have been studied since the 1960s. In broad term, learning opportunities include opportunities to process input, to interact with one or more interlocutors, to produce output, to receive feedback and the like. In the present study, learning opportunities refer to the opportunities for students to be engaged, to negotiate meaning, to make as many oral contributions as possible in classroom interaction, and to interact in a low-anxiety environment. However, there is still a lack of empirical studies about the influence of teacher talk on learning opportunities. This paper seeks to assess learning opportunities in EFL classroom teacher-student interaction, identify specific types of teacher talk that create or obstruct learning opportunities, and explore the possible factors that influence teacher talk on the teacher’s side. Based on the theoretical assumption that learning is a dynamic and constantly shifting social process, the present study adopts that teacher-student interaction resembles real conversation. The present study is a case study which collected data from three senior high school English teachers in Chaoyang District, Beijing. Recorded English reading classes, stimulated recall and semi-structured interviews served as the sources of data. All the data were carefully transcribed and analyzed with the approach of conversation analysis. The results of data analysis show that the status quo of learning opportunities is barely satisfactory, and that teachers’ language use can have profound influence on the construction and obstruction of learning opportunities. In addition, constructive teacher talk has been identified such as content feedback and encouragement; some teacher talk is obstructive like teacher interruption and overuse of native language. What’s more, the study finds that teacher’s belief and language competence are two major factors influencing teacher talk. Therefore, it is implied that teachers should be more aware of their language use and the dynamic nature of classroom context, so that accurate moment-by-moment decisions of language use can be made and learning opportunities can be maximized. Besides, teachers should gain more knowledge about teacher talk and learning opportunities, and be encouraged to do action research so that they can reflect on their own classes and improve their strategies of language use. While the study still has some limitations, for instance, the reading classes recorded from three teachers do not contain the same teaching contents, which might be an external factor that influences the number of learning opportunities. In general, the study has significance for classroom teaching practice and provides some insight for teacher development.