1.3    Theoretical Basis of the Research
Classroom teaching is usually regarded as an interactive process. Krashen’s input hypothesis (1981, 1985) takes the understanding of language input as the basic way to language acquisition. Therefore, what is the most important thing for language teaching is to let the learners accept comprehensive input as much as possible. Long’s interaction hypothesis (1983) consents Krashen’s input hypothesis (1981, 1985) about the importance of comprehensive language input, and it puts much emphasis on the positive function of conversational instruction. Long (1983) argued that two-way communication do better than one-way communication in language acquisition. Because one has the opportunity to inform the other when he/she cannot understand, which contributes to conversational instruction and interactional modification, so language input can be better understood. Swain’s output hypothesis (1985: 248-249, 1993: 158-164, 1995) treats comprehensive input as an important but not sufficient condition. Learners themselves need to use language appropriately to make their target language as accurate as native speakers do. Swain (1985: 248-249, 1993: 158-164, 1995) emphasizes that language output improves language acquisition only when learners are pushed forward, which means they feel the needs to improve and develop their target language. All these theories mentioned above suggest the important effect of classroom interactions to language acquisition, which provide theoretical frameworks for the present study. Teachers’ questioning is an essential tool for teacher-students interactions. On the basis of above theories, effective teachers’ questioning is required to provide comprehensible language input as much as possible and offer opportunities to acquire language through meaningful use of language for learners, and encourage conversational consultation.

1.4     Layout of the Thesis
The thesis generally consists of five chapters. First of all, it is an introduction, which presents the research background of the present research, the purposes and significance of the research, the theoretical basis of the research and the layout of the thesis. Chapter two is literature review which deals with previous definitions about teachers’ questioning, and presents a brief introduction of previous researches on teachers’ questioning both abroad and at home with regard to the types of teachers’ questions, teachers’ wait-time for answers, teachers’ questioning distribution, the techniques of teachers’ questioning, reflection of questioning and teachers’ feedbacks to students’ responses. In addition, this chapter reviews the previous studies on teachers’ pragmatic identities in classroom. In Chapter Three, methodology is introduced. It is composed of research questions, procedures of data collection and data analysis. Chapter four copes with results and discussions, which is the main body of the thesis. This part provides analysis of the results in relation to the research questions based on the classroom investigation, the questionnaire to teachers and students. Factor of teacher’s pragmatic identity, which has an effect on the results, is also discussed. Also, the similarities and differences of the findings between the present research and previous studies are mentioned. At the end of the thesis, conclusion is drawn briefly. The major findings of the study are summarized. Additionally, implications, limitations of the study and recommendations for further research are involved in this chapter.

2 Literature Review
2.1 Definition of Teachers’ Questioning
Classroom teaching is the major channel for students to learn English. In China, English teachers play the key roles as guides and supervisors in teaching, and teacher talk is an important area for English teaching research, which is not only the significant tool for English teaching but also the major source of target language input. According to Nunan’s definition, “teacher talk refers to a variety of language used by teachers when they are in the process of teaching”(Nunan, 1991). “Teacher talk” is very important, both for the organization of the classroom and students’ second language acquisition. As an important part of teacher talk, teachers’ questioning is one of the most common and frequent teacher talks. Kauchak and Eggen (2003) stated in Learning and Teaching that teachers’ questioning not only allow the teacher to assess students’ current grasp of the topics that are studied and facilitate students to integrate new knowledge with the previous in an informal way, but also stimulate students’ enthusiasm to participate in class and promote students to think and solve problems. Therefore, the great influence of teachers’ questioning on teachers’ teaching and students’ foreign language acquisition cannot be ignored. Teachers’ questioning in class has been studied by researchers both abroad and at home and they made main contributions to the classification of questions, questioning distribution, wait-time for answers, questioning techniques, feedbacks of students’ responses and functions of teachers’ questioning. 英语专业课堂中教师提问策略的研究(3):http://www.youerw.com/yingyu/lunwen_15405.html