So if a noun does not occur in the same sentence with the word about which we are in doubt as to whether it is a pronoun or adjective, it is a pronoun or word used in place of a noun. For example, in the sentence, This book is good but that is better; book is understood after the word that and left out to avoid tiresome repetition of the word book. Therefore that is an adjective in this sentence. But if I say, This is good, but that is better; there is no noun understood, for there is no noun in the sentence which we can supply with this and that. Therefore in this sentence this and that are pronouns, used in place of the noun. And since this and that, when used as adjectives, are called demonstrative adjectives; therefore when this and that, these and those, and similar words, are used as pronouns they are called demonstrative pronouns.
260. Be careful not to confuse the possessive pronouns with adjectives. Possessive pronouns modify the nouns with which they are used, but they are not adjectives, they are possessive pronouns. My, his, her, its, our, your and their are all possessive pronouns, not adjectives. Also be careful not to confuse nouns in the possessive form with adjectives.
ADJECTIVES AS NOUNS
261. Sometimes you will find words, which we are accustomed to look upon as adjectives, used alone in the sentence without a noun which they modify. For example, we say, The strong enslave the weak. Here we have used the adjectives strong and weak without any accompanying noun. In sentences like this, these adjectives, being used as nouns, are classed as nouns. Remember, in your analysis of a sentence, that you name every word according to the work which it does in that sentence, so while these adjectives are doing the work of nouns, we will consider them as nouns.
These words are not used in the same manner in which demonstrative adjectives are used as pronouns. There is no noun omitted which might be inserted, but these adjectives are used rather to name a class. As, for example; when we say, The strong, The weak, we mean all those who are strong and all those who are weak, considered as a class. You will find adjectives used in this way quite often in your reading, and you will find that you use this construction very often in your ordinary speech. As, for example:
- The rich look down upon the poor.
- The wise instruct the ignorant.
Many examples will occur to you. Remember these adjectives are nouns when they do the work of nouns.
ADJECTIVES WITH PRONOUNS
262. Since pronouns are used in place of nouns, they may have modifiers, also, just as nouns do. So you will often find adjectives used to modify pronouns. As, for example; He, tired, weak and ill, was unable to hold his position. Here, tired, weak and ill are adjectives modifying the pronoun he.
263. We often find a participle used as an adjective with a pronoun. As, for example: