The goals of this study were to explore students' perceptions of how teachers' science teaching matched students' understanding and needs levels, report on the development and validation of a questionnaire to probe these perceptions, and compare junior high school students' perceptions from Taiwan and Australia. Descriptions of both the pilot study and the main study are included. Taiwanese students (N=1800) and Australian students (N=500) responded to the questionnaire which employed a conceptual framework of four categories: (1) instructional repertoire; (2) representational repertoire; (3) knowledge of students' understanding; and (4) knowledge of subject matter. Examination of the mean data for these categories indicates that there is little difference between the perceptions of Taiwanese and Australian students about their teachers' knowledge. The instrument is useful for teachers in identifying students' perceptions of their own teaching performance. Contains 18 references. (DDR)