This study examined the time constraints imposed on teacher interns by the fact that they enter a classroom already established and owned by a cooperating teacher and leave the scene before the actual year-end closure. Participants in the study were eight secondary language arts student interns. Separate case studies were completed for each intern, based on structured and unstructured interviews, journal accounts, classroom observations, and a preliminary questionnaire. Two aspects of planning driven by time were identified: (1) the rhythm of school, the constraints of time, and instructional pacing, i.e., technical control; and (2) planning by thematic units, activities, and daily plans. The participants felt that the 14-week internship was too short to develop the interpersonal relationships identified as critical to teaching, and too long to be in another teacher's classroom. (JD)