Constructivist professional development give teachers time to make explicit their understandings of learning (e.g., is it a constructive process?), of teaching (e.g., is a teacher an orator or a facilitator, and what is the teacher's understanding of content?), and of professional development (e.g., is a teacher's own learning best approached through a constructivist orientation?). Furthermore, such professional development provides opportunities for teachers to test their understandings and build new ones. Training that affects student-centered teaching cannot come in one-day workshops. Systematic, long-term development that allows practice - and reflection on that practice - is required.