In English composition, we have the so-called demonstrative reference words as handy devices for making our point more immediate and forceful without unduly repeating ourselves. We will recall that they come in these three categories — the demonstrative adjectives, the demonstrative pronouns, and the demonstrative adverbs.

Demonstrative adjectives. This category consists of the modifiers 'this,' 'that,' 'these,' and 'those.' They belong to the class of function words called determiners, which serve to either identify nouns or word groups functioning as nouns or give additional information about them. The demonstrative adjectives always agree in number with the nouns they modify — 'this' and 'that' for singular nouns, as in 'this apple' and 'that woman,' and 'these' and 'those' for plural nouns, as in 'those apples' and 'those women.'