数列极限的ε－Ｎ定义是极限概念的基础，通常比较难理解。笔者通过从直观描述到精确的定义，逐步深入来讲述ε－Ｎ，ε－δ，就其语言教学的难点，提出解决问题的方法 The ε-N definition of numerical limits is the basis of the concept of limits and is often difficult to understand. By direct description and accurate definition, the author tells us about ε-N, ε-δ gradually and puts forward some solutions to the problem of language teaching