Pronouns are words that may be used in place of a noun in a sentence. Pronouns can often be identified by looking for the short words in a sentence that take up less space than the names of the people, places, and things they replace, according to Cambridge University Press.
There are multiple types of pronouns. Their use is determined by both the type of noun being replaced and its function within the original sentence, as the Online Writing Lab at Purdue University explains. The British Council also points out that subject pronouns are identifiable by the fact that they are the subject of the verb. Likewise, object pronouns can be identified by finding the object of the sentence, or by looking at the word which comes directly after a preposition. Cambridge University Press also indicates that prepositions can also be used to replace noun phrases. These can be identified by finding two or more words that offer both a noun and at least one modifier. There are of course, other prepositions used in English as well. Cambridge University Press classifies all prepositions as belonging to one of the following groups: personal, possessive, reflexive, interrogative, demonstrative, indefinite, reciprocal, and relative.