Krashen, S. (1982). Principles and practice in second language acquisition. New Jersey: Prentice Hall International.
摘要：This text explores the relationship between second language teaching practice and what is known about the process of second language acquisition and summarizes the current state of second language acquisition theory.
-- Draws general conclusions about the application of theory to methods and materials and describes the characteristics that effective materials should include.
-- Concludes that language acquisition occurs best when language is used for the purpose for which it was designed: communication.