Introduce nouns

EG A, AN, THE, THIS, SOME

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.

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.”

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.”