What is the meaning of this that these those?
This, That, These, Those - Demonstratives - The English Space This, that, these, and those are demonstratives. They can replace or modify a noun. This, that, these, and those are demonstratives. They can replace or modify a noun.
Are these/these and that/those always used with nouns?
A good question. We use that to show distance in time as well as distance in space. Are this/these and that/those always used with nouns? No, we can use them as pronouns, without nouns, when it's obvious what they refer to.
Why do we use 'this' and 'that' in English?
We can use 'this' and 'that' by themselves exceptionally to talk about people when we say who the person is. This happens when we introduce people and on the telephone. When we're on the telephone, in UK English, we use 'this' to say who we are and 'that' to talk about the other person.
This that