本节课教师把教学活动划分为课前自主学习和课堂学习(内化知识、拓展能力)两个循序渐进的阶段.教师先安排学生课前完成自主学习任务单给出的学习任务,而后进入课堂学习环节,由师生共同提炼升华归纳出本质,然后利用本质规律解决综合问题.本案例充分展现了翻转课堂形式下课堂的高效性. Teachers of this lesson classify teaching activities into two gradual stages of self-learning before class and class learning (internalization of knowledge and ability to expand), and teachers first arrange the learning tasks given by the autonomous learning task sheet prior to the class and then enter the classroom In the learning process, the teachers and students refine and subtly extract the essence, and then use the essential law to solve the comprehensive problem.This case fully demonstrates the efficiency of the classroom in the form of overturned classroom.