初中化学课程标准指出,化学教育要帮助学生形成终身学习的意识和能力,教学中将科学探究作为课程改革的突破口,激发学生的自主创新意识,从而提高学生的科学素养。由此可见,初三化学教学不仅仅局限于有限的课堂时间,更要贯穿于课前、课中、课后各个阶段。其中,有效课前预习的重要性不言而喻,它不仅可以使学生了解课程的重点和难点,而且能促使学生产生浓厚的学习兴趣。笔者使用的是沪教版教材,在所执教的初三化学课 Chemistry curriculum standard of junior high school pointed out that chemistry education should help students to form the awareness and ability of lifelong learning. In teaching, scientific inquiry should be used as a breakthrough point of curriculum reform to stimulate students ’awareness of independent innovation so as to improve students’ scientific literacy. This shows that the first three days of chemistry teaching is not limited to a limited class time, but also throughout the pre-class, class, all stages of after school. Among them, the importance of effective pre-lesson preparation is self-evident, which can not only make students understand the focus and difficulty of the course, but also can promote students to have a strong interest in learning. The author is using the Shanghai teaching materials, taught in the third day of chemistry classes