Abstract:With 72 freshmen of non-English majors as the subjects, the present study explored the effects of input frequency of different occurrences and output frequency of different occurrences on the acquisition of second language chunks' productive knowledge. The study results showed that (1) input frequency of different occurrences had an effect on the immediate acquisition of second language chunks productive knowledge, and had a delayed effect in one week; (2) output frequency of different occurrences had an effect on the acquisition of second language chunks' productive knowledge in one week, and the delayed effect remained in two weeks; (3) there were significant differences between the effects of input and output frequency of different occurrences on the acquisition of second language chunks' productive knowledge. The study will not only enrich the understanding of explicit/implicit teaching and effects of frequency, but also provide pedagogical implications for chunk teaching.