This case study explored how a teacher, Ms. Walter, and her students experienced a unit of study on market structures in an Advanced Placement (AP) Microeconomics course. We employed qualitative research methods, drawing on the work of Nuthall and Alton-Lee, to connect students' experiences of classroom instruction to their reasoning on an end-of-unit multiple-choice test modeled after the AP Exam. Findings indicate a key misalignment between opportunities to learn the content during the unit and student performance on the unit test. Despite engaging in student-centered, interactive methods of instruction, students were unable to engage in the tasks required by the assessment.