In English, we can use demonstrative pronouns like this, that, these and those to replace something already mentioned before.
We use this and that in the singular form. We use these and those in the plural form.
These is the plural of this and those is the plural of that. Also, we use this and those when the thing or the person are near us and we use that and those when they are far from us.
Examples:
This bag is beautiful/ These bags are beautiful .This boy is very tall/ These boys are very tall
That country is the largest one on the continent
Those countries are the largest ones on the continent.
Can you see that beautiful star in the sky
Look at those stars !.
