instance: applies to any individual person, act, or thing that may be offered to illustrate or explain, or prove or disprove a general statement: an ~ of history repeating itself.      （general两个意思，1通用即适用于大多数，2总体大概。这里是第二个意思: 概述）


case: applies to an instance that directs attention to a real or assumed occurrence or situation that is to be considered, studied, or dealt with: a ~ of mistaken identity.


illustration: applies to an instance offered as a means of clarifying or illuminating a general statement: an ~ of Murphy's law. （墨菲定律Murphy's law: 事情往往会向你所想到的不好的方向发展，只要存在这个可能性。If there are two or more ways to do something, and one of those ways can result in a catastrophe, then someone will do it. 假如一片涂有果酱的面包掉到地毯上，常常是带果酱的一面落在地毯上）


example: applies to a typical, representative, or illustrative instance or case: a typical ~ of bureaucratic waste.


sample: implies a random part or unit taken as representative of the larger whole to which it belongs: show us a ~ of your work.


specimen: applies to any example or sample of a whole or to an example or sample carefully selected to illustrate important or typical qualities: one of the finest ~s of the jeweler's art.


instance例子: 用于解释或证明某观点的独立的人或事物，case案例: 指需要考虑研究应对其相关情况的例子，illustration例证插图: 用于澄清阐明某观点的例子(illuminate阐明照明)，example例子: 表示典型代表性阐释性的例子，sample样本: 指随机采样的样本，认为能代表整体，specimen样本标本: 用于阐释某属性的任意或精选例子


记忆方法: 1) 首字母ICIESS排列成ISS国际空间站和ICE移民及海关执法局<==联想记忆的例子    ICE是Immigration and Customs Enforcement移民及海关执法局的缩写    ISS是International Space Station国际空间站的缩写   

              2) 例子的意思是展示所属类型特性的事物mean something that exhibits the distinguishing characteristics of the category to which it belongs.首字母ICIESS排列成ISS国际空间站和ICE移民及海关执法局<==联想记忆的例子       category泛指类型类别=a group of people or things，不像class那样正式