1)指示代词分单数( this/ that)和复数( these/ those)两种形式，既可作限定词又可做代词，例如：

单数　复数

限定词： This girl is Mary. Those men are my teachers.

代词： This is Mary. Those are my teachers.

2)指示代词的句法功能

指示代词主要有四个，即 this, that, these和 those。它们在句中可作主语、宾语、表语、定语等。

This is my book.(主语)

I want that.(宾语)

My book is that.(表语)

I like that dress.(定语)

注意：

1. 为避免重复，可用 that和 those代替前面提到的名词。如：

The playground of this school is bigger than that of that school. ( That= the playground)

My seat is next to that of the mayor.( that= mayor's seat)我的座位在市长座位旁边。

2. 用来回指上文提到的事情时，可用 this或 that，但是若要指下文叙述的事情，通常要用 this。如：

- - She is a beautiful girl.

- - Who said that?

I want to know this: Is she beautiful? 我想知道这一点：她美吗

3. 在打电话时，通常用 this指自己，用 that指对方：

Hello. This is Jim. Is that John? 喂，我是吉姆，你是约翰吗

4. 除用作代词外， this和 that还可用作副词，用以修饰形容词或副词，意为"这么"、"那么"，相当于 so。

如：

I've done only that much. 我所做的就这么多。

Is he always this busy? 他总这么忙吗

5. 指示代词 this, that和 these在作主语时可指物也可指人，但作其他句子成分时只能指物，不能指人。而 those作宾语后接定语从句时可以指人。而且只有 that、 those后面可以跟定语从句。

如：(对) That is my teacher. 那是我的老师。( that作主语，指人)

(对) He is going to marry this girl. 他要和这个姑娘结婚。( this作限定词)

(错) He is going to marry this. ( this作宾语时不能指人)

(对) I bought this. 我买这个。( this指物，可作宾语)

He admired those who looked beautiful. 他赞赏那些外表漂亮的人。( those指人)

(错) He admired that who danced well. ( that作宾语时不能指人)

(对) He admired that which looked beautiful. 他赞赏外表漂亮的东西。