化学新课标强调:我们以“学生的发展为本”作为基本出发点,不仅注重学生发展的全体性、全面性、主动性,而且注重发展的差异性和持续性。因此重视课堂教学中的预设和生成性是时代的呼吁,教学中的生成性是不确定的、动态的、个性的。这样使得课堂教学不再是引导学生进入教师精心准备的“模式里”来实现教学目标,而是师生在教学情景中通过交流、师生互动,因势利导,把静态的课堂变得生动、有活力。课堂教学中的预设和生成是 The new chemistry curriculum emphasizes: “We regard” the development of students as the basis “as the basic starting point, not only focusing on the overall, comprehensive and initiative of students’ development, but also focusing on the differences and sustainability of development. Therefore, paying attention to the presupposition and generativeness in classroom teaching is the call of the times. The generativeness in teaching is indefinite, dynamic and individual. In this way, classroom teaching is no longer to guide students into the ”model " in which teachers carefully prepared to achieve the teaching objectives, but teachers and students in the teaching scenarios through the exchange, teacher-student interaction, make the best use of the static classroom becomes vivid, Vibrant. The default and generation in classroom teaching is