指示代词是语言中用于明确指代人或事物的工具，this, these, that, those 是日常交流中最常用的四个，它们的核心区别体现在距离远近与单复数上，用法则需结合具体语境。
从距离与单复数来看，this 和 these 指向离说话人近的对象，this 搭配单数名词，these 搭配复数名词；that 和 those 指向离说话人远的对象，that 搭配单数名词，those 搭配复数名词。比如指着手边的笔记本说“This notebook is mine”，拿起桌上的几支笔说“These pens are new”；望向窗外的树说“That tree is very tall”，指向远处的几朵花说“Those flowers look beautiful”。
指代人时，近距离介绍用 this，如“This is my sister, Lily”；询问远处的人用 that，如“Who is that standing by the gate?”电话交流中，自我介绍用 this，“Hello, this is Tom speaking”，询问对方用 that，“Is that Mary?”
指代上文提及的内容时，常用 that 或 those 避免重复。单数概念用 that，如“The idea you mentioned is good, but that of the manager is more practical”that 指代 idea；复数概念用 those，如“The books on the desk are heavier than those on the shelf”those 指代 books。
时间维度上，this 常指向当前或近期的时间，如“I have a meeting this morning”“This weekend we’re going hiking”；that 可指向过去的时间，如“That summer we traveled to the coast”“I saw him that night”。
口语中，these 和 those 还可单独使用，省略名词，如“These are my keys”“Those look delicious”；this 和 that 也可表或评价，如“This is the best gift ever”“That was a terrible mistake”。
总的来说，this/these 近指、单复数分明，that/those 远指、单复数对应，结合距离、数量和语境，就能准确运用这四个指示代词。