Demonstrative adjectives
Demonstrative adjectives have two singular forms (this, that) and two plural forms (these, those).
Demonstrative adjectives are used to explain whether the noun or nouns we are talking about are singular or plural, and whether they are close to us or not.
'This' and 'these' are used to talk about nouns that are close to us. In simple terms, 'this' and 'these' are used to refer to nouns which are 'here'.
'That' and 'those' are used to talk about nouns that are distant, or not close to us. In simple terms, 'that' and 'those' are used to refer to nouns which are 'there', or 'not here'.
These books are too expensive.
This car is beautiful.
That man really irritates me!
This hotel is much more expensive than that one.
Demonstrative pronouns
Demonstrative pronouns have the same form as demonstrative adjectives; this, that, these, and those. Demonstrative pronouns are also used to identify specific people or things, but are used as pronouns, without the nouns that they refer to.
This bread is fresher than that.
How much are those?
Would you like a little of this?
That seems very strange!