《基础教育课程改革纲要(试行)解读》指出:“课堂教学不应当是一个封闭系统,也不应拘泥于预先设定的固定不变的程式”。课堂教学是人的教学,人是活泼的、开放的、差异的,师生的一个闪念、一个举动、一个误会、一个忘形,都可能会增加教学中的非预期因素,这些“即兴创造”的随机事件会不同程度地影响教学进程。但如果处 The Basic Education Curriculum Reform (Trial) Interpretation states: “Classroom teaching should not be a closed system, nor should it be rigidly bound to a pre-set fixed program.” Classroom teaching is human teaching, people are lively, open, different, a flash of teachers and students, a move, a misunderstanding, forgetfulness, may increase the teaching of unexpected factors, these “improvisation to create ”Random events will affect the teaching process to varying degrees. But if at