In this article, we report on efforts to develop a set of Web-based teaching simulations within the LessonSketch platform to support shifts in how preservice elementary teachers (PSTs) enact and evaluate their questioning practices in response to specific examples of students' mathematical thinking. The simulations included storyboard depictions of classroom situations, along with prompts for the PSTs to first analyze mathematical thinking and then construct, select, and analyze the effects of possible teacher questions. Participants included 54 PSTs across 5 sections of a mathematics content/methods class. Data were analyzed to document how PSTs enacted and reflected on their questioning practices in the context of these LessonSketch simulations. In this article, we focus on 2 storyboard depictions of classroom situations and describe how each appeared to provide different opportunities for PSTs to revise their ideas about questioning.