Here's a breakdown of their function:
1. Identifying a specific item:
* This and these refer to things that are near the speaker.
* "This book is interesting." (The speaker is holding the book)
* "These shoes are too small." (The speaker is looking at the shoes)
* That and those refer to things that are farther away from the speaker.
* "That car is fast." (The car is in the distance)
* "Those flowers are beautiful." (The flowers are across the street)
2. Replacing nouns:
Demonstrative pronouns can replace nouns to avoid repetition.
* "I have a new phone. This is much better than my old one."
* "Look at those birds! Those are my favorite kind."
3. Adding emphasis:
Demonstrative pronouns can be used to emphasize a particular item.
* "This is the day we've been waiting for!"
* "Those are the people who helped me."
4. Creating contrast:
Demonstrative pronouns can be used to highlight a difference between two things.
* "I like this apple better than that one."
* "These shoes are comfortable, but those are stylish."
In summary:
Demonstrative pronouns serve as pointers, helping us identify specific people, places, or things. They clarify which item is being referred to, replace nouns, add emphasis, and even create contrast.