Demonstratives Definition

A demonstrative indicates whether something is near or far from the speaker or writer and also shows singular or plural:

This book (singular, near)

That book (singular, distant)

These books (plural, near)

Those books (plural, distant)

A demonstrative can be used as a determiner or a pronoun:

EG 1: Could you pass me those leaflets? (determiner)

EG 2: Give me that. (pronoun)