The adjective is undoubtedly one of the grammatical elements more notable and important at the behest of a sentence or an expression, while it occupies that privileged place along with other important elements such as the noun, adverb, article, verb, among others.
The main mission of the adjective is accompany the noun, to complete or limit its meaning. There is always an agreement between the gender (masculine or feminine) and the number (singular or plural) of the noun with that of the adjective that accompanies it.
However, adjectives have a classification that delimits them into various types, the ones that interest us in this review are demonstrative adjectives.
In the specific case of demonstratives, their primary function is point out the relationship of place or also of time, giving an account of the closeness that one has, with a person with whom one is speaking or about whom one is speaking.
One way to recognize them and not make mistakes in terms of their application is that they must always precede the noun they affect: This house is the one I liked the most of all the ones we saw today.
This, that, that and that and their respective variants in gender and number, are some of the most used demonstrative adjectives.
Now, there are degrees of distance in the form of adjectives of this type, the first degree of distance being: (this / these / this / these), the second degree of distance: (that / those / that / those) and the third degree of distance: (that / those / that / those).
When we want to indicate that something is close to the speaker, the first degree of distance is used (This skirt is not the one I chose); meanwhile, when we want to indicate that something is close to the listener, the second degree of distance is used (that suitcase cost a lot of money); and the third degree of distance is used mostly when you want to indicate that something is far, both from the speaker and the listener (that past time was undoubtedly better).