预设主要是指在教育教学的过程中对教学目标、教学内容、教学进度和教学方法与手段的预设。然而教师不可能预设课堂教学中发生的一切。新课改提出,教学不只是单向、封闭、静态的知识授受过程,而是师生多向、开放和动态的对话、交流过程,这就意味着教学过程存在着众多不确定的因素:课堂中教师产生了没有预设到的情况或学生有了与众不同的思考和疑问,这就 Preset mainly refers to the teaching objectives, teaching content, teaching progress and teaching methods and means in the process of education and teaching of the default. However, it is impossible for teachers to preset what is happening in classroom teaching. The new curriculum reform proposes that teaching is not just a one-way, closed and static process of imparting knowledge, but a process of multi-directional, open and dynamic dialogue and exchange between teachers and students. This means that there are many uncertainties in the teaching process: In the absence of teacher pre-set conditions or students have distinctive thoughts and questions, which