We have seven types of pronouns: (1) personal, (2) reflexive and intensive, (3) indefinite, (4) demonstrative, (5) relative, (6) interrogative, and (7) reciprocal.
You must commit to memory some of the basic rules governing the correct use of pronouns. A summary looks like this:
1. Personal Pronouns. Personal pronouns appear in three cases: subjective, objective, and possessive.
Good writers make certain they use the proper case, so you must review the section on nouns and relearn the grammatical functions of subjects (subjective case), subject complements (subjective case), direct objects (objective case), objects of verbal phrases (objective case), and objects of prepositions (objective case). You’ll use possessive case for those pronouns replacing nouns that would appear with possessive endings.
Pay attention to the rules on agreement in number and agreement in gender. When you have a generic antecedent, try to make it plural to avoid having to pick he over she or she over he. Picking one over the other might be viewed as sexist writing. As the language continues to evolve, the plural pronouns they-their-them will one day be regarded as the proper pronouns to use when referring back to singular, generic antecedents. But be aware of your audience. In formal settings, follow the old, traditional rule of agreement in number.
Make sure you use the reflexive only when the subject of the sentence and an object are the same person.
The word everybody is singular and, in formal settings, requires a later singular pronoun (he or she, him or her, his or her, his or hers). These days, however, you can use the plural pronouns they-their-them to refer back to singular indefinite pronouns. To avoid sexism, don’t use the indefinite pronoun; instead, try to make the antecedent plural (use people, persons, or type of group, such as writers) so that you may then use they, their, or them.
Make sure the this has a readily identifiable antecedent, either a noun, noun phrase, or entire idea. Ask yourself, “this what?” If an answer immediately comes to mind, the usage is probably OK.
You must learn to distinguish among who (subjective), whom (objective), and whose (possessive). Watch for verbs in the clauses that have no other word acting as the subject; these will always require who. If the verb has some other subject, whom or sometimes whose is always correct.
Learn the differences between that (introduces restrictive clause) and which (introduces nonrestrictive clause and is set off by commas). We’ll return to these tricky words in the eBook Developing a Powerful Writing Style.
These do have possessive forms, but only in the singular: each other’s and one another’s.