在中等学校中所学的化学知识是基本知识,这些知识对于任何人不论他将来从事什么活动,都是需要的,但是只有当人们牢固地掌握了这些知识的时候,才能运用这些知识。大家知道,新知识是在旧知识的基础上学习的,旧知识如果还没有巩固,学习新知识自然会有困难。学生只有把学过的知识巩固地掌握了之后,才能够顺利地获得新知识。因此,在教学过程中贯彻巩固性原则,对学生获得巩固的知识是具有重大意义的。化学是研究物质及其变化的一门科学,世界上物质的种数是那样地多,我们虽然不一定每一种物质都一一要加以研究,而只要研究一些对人类关系较大的且具有代表性的物质,但即使这样,所要研究的物质种数还是很多的。而且每种物质都有它自己的成分,特 Chemical knowledge learned in secondary schools is a basic knowledge that is needed for anyone regardless of what he or she will do in the future, but only if people have a firm grasp of it. We all know that new knowledge is learned on the basis of old knowledge. If the old knowledge has not been consolidated, learning new knowledge naturally has its own difficulties. Only when students have mastered the learned knowledge can they successfully acquire new knowledge. Therefore, it is of great significance to implement the principle of consolidation in the teaching process and acquire the consolidated knowledge of students. Chemistry is a science that studies matter and its change. There are so many kinds of matter in the world. Although we do not have to study every kind of matter one by one, we should study some things that are of great human relation and have Representative of the material, but even so, the number of species to be studied is still very large. And each substance has its own ingredients, special