集合的初步知识 ,是掌握和使用数学语言的基础 ,是学习函数及其他后续内容的门坎 .集合是由元素组成的 ,集合中的元素具有确定性、互异性和无序性 ,集合中的许多概念 ,如子集、空集、全集与补集、交集与并集等都是以元素来定义的 ,所以认清元素的特征和性质 ,并从元素入手是学 The initial knowledge of the collection is the basis for mastering and using the mathematical language, and it is the threshold for the learning function and other follow-up content. The collection is composed of elements. The elements in the collection are deterministic, heterosexual, and disorderly. Many of the collections Concepts such as subsets, empty sets, unions and complements, intersections and unions are defined by elements, so recognizing the characteristics and properties of elements and starting from elements is