众所周知,命题一般都是由条件和结论两部分组成,研究命题就是研究条件和结论两部分之间的关系;而充要条件正是刻划这种关系的重要概念之一。由于充要条件在中学数学中既是重点又是难点,本文根据自己多年的教学实践,谈谈充要条件这个难点的突破及逐层深化概念的一些体会。 As we all know, propositions are generally composed of two parts: condition and conclusion. The research proposition is the relationship between the conditions and conclusions of the study. The necessary and sufficient conditions are just one of the important concepts that characterize this relationship. Because the necessary and sufficient conditions are both important and difficult in middle school mathematics, this article, based on his own teaching practice for many years, talks about the difficulties in terms of sufficient and necessary conditions and deeper understanding of concepts.