【正文】 ______________ 7 ment and summary of foreign country’s research. We should make our new research and find more novel results. Secondly, the subject is too simple. From the previous research at home, we can find that most of the subject of TT is all about inservice teachers in middle school and in university, only few of them involve in student teachers. As is known to all, student teacher is a very crucial power in teaching. But they have just entered the society and begin the career of teaching, so they lack experience. Therefore, doing research on the TT of student teachers can give some suggestions on teaching for student teachers and make preparation for their teaching career. Last but not least, from the previous researches, the author finds that none of the researches at home are about the student teachers themselves. Discovering this research gap, the author decides to make a research of TT based on hers, and try to find some ways to improve her own TT. Comprehensible Input Hypothesis Krashen(1981,1985) figured out five hypothesis of language acquisition: Language acquisitionlearning hypothesis, monitor hypothesis, the natural order hypothesis, language input hypothesis and Affective Filter Hypothesis. Among them, language input hypothesis is the core for language acquisition. The Input Hypothesis states that learners progress in their knowledge of the language when they prehend language input that is slightly more advanced than their current level． Krashen called this level of input “i+1”． Where “i” is the language input and “+1” is the next stage of language acquisition． The AcquisitionLearning Hypothesis claims that there is a strict separation between acquisition and learning； Krashen saw acquisition as a purely subconscious process and learning as a conscious process and claimed that impro vement in language ability was only dependent upon acquisition and never on learning． The Monitor Hypothesis states that consciously learned language can only be used to monitor language output； it can never be the source of spontaneous speech． The Natural Order Hypothesis states that language is acquired in a particular order and that this order does not change between learners， and is not affected by explicit instruction The Affective Filter Hypothesis states that learners’ ability to acquire language is constrained if they are experiencing negative emotions such as fear or embarrassment． At such times the affective filter is said to be “up”. The Input Hypothesis has been applied in language teaching pervasively. It has been found out that, at the beginning level of learning a language， class time is filled with prehensible oral input。 Liu Shaozhong, 20xx). In 1975, Sinclair and coulthard do deeper research and classification of TT in terms of its instruction, reaction and feedback, and they renew and brought up the threeways format of IRF, which engendered great impact at that time. (Yan Guidong, 20xx). In a word, the class they focus on is still the teacheroriented class. When it es to 1980s, the studies on teacher talk have entered into a booming period. With the development of the study on language acquisition, researchers make a deep and painstaking microanalysis on teacher talk through which teachers and students could better create learning opportunity together. Clyne(1981), Freed(1980,1981), Chaudron and other scholars had great interest on the modification of TT. They focused on the speed modification and rhythm modification (including its tone, pronunciation, stress and stop) (Zhao Changyou, 20xx). When pared the TT of second language acquisition class with that of other language context, the speed of TT in the second language learning classroom is slower. Since 1980, more and more scholars have started to study teacher talk from the perspective of semantics and pragmatics. Some studies pay attention to the expressing effect of teaching language while some lay emphasis on the background of using teaching language. The analysis of TT is not to observe every classroom action of teachers’, but to take the interaction between teacher and student as a whole, and lay emphasis on analyzing the nature and structure of TT (Ellis, 1990). To sum up, after reviewing the research on TT abroad, conclusion can be drawn that since 1950s, teacher talk has gradually became a new field with which researchers are much more concerned, many scholars began to conduct research on TT and the study on TT have entered into a booming period since 1980s. Studies on TT At Home In recent years, Chinese scholars have made some experiments on the project of English classroom teaching, and some of them are related to TT. Yet such research hasn’t been paying much attention, and most of their works are all about the introduction and summary of the researches abroad (Li Lishengamp。(3)logicality(have logic in presenting and explain language point。( 2) Acceptability and prehensibility. It is suggested that teacher adjusts his own language according to the level of students, so as to help An Action Research of Improving a Junior English Preservice Teacher’s Teacher Talk __________________________________________________________________________ 4 students understand and accept. (3) Repetitiveness. The repetition of TT is to arouse students’ attention to some important points and difficult points. (4) Teacher’s characteristics. Different teachers have different TT because of their characteristics。 two, as the target language of English class teaching, and thus be distinguished from other teacher talk of other subject. The definitions of teacher talk are different from one to another, but there is something in mon: they are all the discourse spoken by the teachers in class. From the discussion above, the author es to the conclusion that teacher tal