There are only five demonstrative pronouns in English: this, that, these, those and such. Demonstrative pronouns can behave either as pronouns or as adjectives.

When used as pronouns, these words identify or point to nouns.

• That was an incredible experience. (Here the demonstrative pronoun that refers to something the speaker just talked about.)
• I don’t believe this. (Here the demonstrative pronoun this refers to something mentioned in a previous sentence.)
• Such was his command over the language. (Here the demonstrative pronoun such refers to an explanation just made.)

As adjectives, the demonstratives modify a noun that follows. We can convey a sense of distance in time and space through the choice of demonstratives.

This and these are used to denote things and situations closer in space and time.

• Get this bird off my shoulder. (Here the reference is to a bird sitting on the speaker’s shoulder. It is very close to him in space.)
• Get that cat off the piano. (Here the reference is to a cat sitting on a piano away from the speaker.)

These and those are the plural forms of this and that.

• Listen to this. (Here we are referring to a situation which is just about to start.)

That and those can be used to talk about experiences which have just finished.

• That was an unforgettable experience. (Here we are talking about something happened in the past.)

Acceptance and rejection

This and these are used to show acceptance or interest. That and those can show rejection or dislike.

• That boy of yours has stained my walls. (dislike)
• Tell me about this new project of yours. (interest)