Ⅰ.Introduction Teachers’ talk is a very important media.According to Nunan,“Teachers’ talk is a key factor to both class- room’s organization and students’ language acquisition, not only because it is a kind of teaching strategy to achieve a better effect,but also because it is a way for teachers to display target language and for students to ex- perience target language.”Contemporary education has de- manded teachers to change their roles from an authority in the traditional classroom to different roles in present I.Introduction Teachers’ talk is a very important media.According to Nunan,“Teachers’ talk is a key factor to both class- room’s organization and students’ language acquisition, not only because it is a kind of teaching strategy to achieve a Better effect,but also because it is a way for teachers to display target language and for students to ex- perience target language.”Contemporary education has demanded teachers to change their roles from an authority in the traditional classroom to different roles in Present