【Abstract】In foreign language learning， it is obvious that teacher， material and leaner are among the substantial factors contributing to the learning process. When it comes to the role of each factor， we have to take many factors into account. Their roles may vary across age， proficiency levels as well as sociocultural， political， and institutional contexts （Brown， 2007）. This article first illustrates the roles of the three factors one by one， and concludes with their relationship briefly.
　　【Key words】Teacher； Material； Learner； Foreign Language Learning
　　1. The role of teacher
　　In a broad sense， teacher acts as facilitator and director of the learning process， but not so much that stifle learners’ creativity. And teachers’ roles should extend to include their cultural and social needs， teaching students goes beyond language issues and enriching themselves by broadening their cultural and linguistic horizons. Furthermore， it would be teacher’s responsibility to make a suitable selection and find the most appropriate and reasonable activities in foreign language course books for children， teenagers or adults and consider which of them provide suitable challenges for learners of the particular age range. If we want learners to become absorbed in the tasks we set them， it is important to provide an appropriate challenge as well as helping the learners to plan appropriate strategies to meet these challenges （Williams