'This' and 'these' are called demonstratives. It means they point to a person or object close to us. This 'closeness' can be physical and temporal, i.e. it can be related to the physical position of the thing or object or it can refer to the nearness in time.
- 'This' is used with singular and uncountable nouns;
- 'These' is used with plural nouns.
You're too old to play with
Uncountable Nouns: This or These?
Uncountable nouns such as water, tea, butter, milk, air, rice, anger, money, information, etc. have no plural form. So, we must use 'this' for indicating them.
You must somehow manage to control
Demonstrative Pronouns: Introducing or Identifying
'This' and 'these' are also used for introducing someone to another or identifying someone or yourself, especially on the phone or at the door. Look at these examples:
Differentiating between Things
If we want to talk about the 'proximity' of things, we can differentiate between things/persons near to us as opposed to things/persons far from us by using 'this/these vs. that/those'. 'This /these' refers to something 'here', while 'that/those' points to something 'there.'
Demonstrative Pronoun or Determiner?
As you might have noticed from the examples, 'this' and 'these' can both be determiners and pronouns. When they are followed by a noun or a noun phrase, they're called 'demonstrative determiners'. On the other hand, if they appear alone, they are called 'pronouns' because they replace a noun phrase.