Demonstrative determiners are an important part of English grammar. They are used to point out specific people, places, or things. In English, there are four demonstrative determiners: this, that, these, and those.

The word "this" is used to point out something that is close to the speaker. For example, "This book is interesting" means that the book is close to the person speaking. In Hindi, "this" can be translated as "यह".

On the other hand, "that" is used to point out something that is far from the speaker. For instance, "That car is expensive" means that the car is far from the person speaking. In Hindi, "that" can be translated as "वह".

When we want to talk about more than one thing that is close to the speaker, we use the word "these". For example, "These pens are blue" means that the pens are close to the person speaking. In Hindi, "these" can be translated as "ये".

Similarly, when we want to talk about more than one thing that is far from the speaker, we use the word "those". For instance, "Those houses are big" means that the houses are far from the person speaking. In Hindi, "those" can be translated as "वे".

It is important to note that demonstrative determiners should agree in number with the noun they modify. For example, we say "This book is interesting" and not "This books is interesting". Similarly, we say "These pens are blue" and not "These pen are blue".

In conclusion, demonstrative determiners are used to point out specific people, places, or things. By understanding and using them correctly, we can effectively communicate in English.