This report focuses on key elements of teaching occurring during intensive, one-to-one instruction with 3rd- and 4th-graders. The study involves six cases in all, each consisting of video records of up to eight lessons, each of 30-45 minutes' duration, resulting in the analysis of about 33 hours of video data. A resulting framework of four stages of analysis of one-to-one teaching is presented and the stage 'During solving a task' is elaborated according to students' responses: correct, partly correct, incorrect, and no response. Three subcategories pertaining to an incorrect response are described and two are exemplified via cases drawn from the data. The cases exemplify how the framework can be applied to analyse or inform intervention instruction and highlight its theoretical and practical importance. [For the complete proceedings, see ED597799.]