课堂导入的目的是引起学生注意、激发学习兴趣、产生学习动机、明确学习方向和建立知识联系。在中学生物教学中,创设和谐的教学氛围,构建良好的教学情境,使教学内容紧扣学生心弦,激发学生求知动力,使其自觉地学习,是提高课堂效率的重要 The purpose of class introduction is to arouse students' attention, stimulate their interest in learning, generate motivation, clarify the learning direction and establish knowledge connection. In middle school biology teaching, creating a harmonious teaching atmosphere, building a good teaching situation, making the teaching content close to the students 'hearts, stimulating students' motivation and making them learn consciously are important to improve classroom efficiency