Determiners: This, that, these, those

This, these

We use this and these for things that are here (near). This is singular and these is plural.

• This is my new watch. 
• These are my sisters Anna and Jenny. 

That, those

We use that and those for things that are there (not near). That is singular and those is plural.

• That man is very strange. 
• I need those boxes over there. 

With a noun or without a noun

We can use this, that, these, those with a noun (this box, that car, etc.) or without a noun.

• This watch is very expensive. 
• I like that woman in the park. 
• Who is that? (= that person)
• ‘What are those?’ ‘They are old pictures.’

This is John (introductions and on the phone)

We use this is when we introduce people and on the telephone.

• Hi, this is Tim. (Tim on the telephone)
• Laura: ‘Hi, Sara. This is my friend Paul.’ Sara: ‘Hi, Paul. Nice to meet you.’

Demonstratives – This, That, These, Those

As mentioned above, demonstratives are words that show which person or thing is being referred to.

In the sentence:

• “This is my brother”,

“This” is a demonstrative

The demonstratives in English are this, that, these, and those

• “This” modifies or refers to a singular noun that is near to the speaker.
• “That” modifies or refers to a singular noun that is far from the speaker.
• “These” modifies or refers to plural nouns that are near to the speaker.
• “Those” modifies or refers to plural nouns that are far from the speaker.

Demonstrative Pronouns Vs Demonstrative Adjectives

A crucial distinction exists between demonstrative pronouns and demonstrative adjectives, each serving distinct grammatical functions.

1. Demonstrative Adjectives: Demonstrative adjectives, also known as demonstrative determiners, modify and provide more information about a noun. They help specify which particular noun is being referred to. Examples include:

• • “This apple is delicious.”
  • “I like those houses.”

1. 
   Demonstrative Pronouns: Demonstrative pronouns, on the other hand, stand independently as substitutes for nouns. They replace the noun rather than modify it. Examples include:

• • “This is delicious.” 
  • “I like those.”