Using pronouns seems simple enough, but they cause confusion because it’s easy to mix up nominative, or subject, pronouns and object pronouns.
Here’s a review of the difference between the two categories of pronoun: A nominative pronoun is one that takes the place of a noun phrase used as a sentence’s subject. Instead of writing, “The man patiently stood in line,” one could write, “He stood patiently in line.”
An object pronoun, however, replaces a noun phrase employed as an object: If you wished to use a pronoun to refer to a woman who precedes the man in line, you wouldn’t use the equivalent of the pronoun that appears in the second example above (“The man patiently stood in line behind she”); you’d use a different form (“The man patiently stood in line behind her”).
Pronouns that rename the subject and follow a verb should also be in subject form: “It is I who have been wronged.”
In comparative sentences — those in which as or than is used to compare two things — should you write, “I am just as capable as her” or “I am just as capable as she”? To test the appropriate pronoun form, append a verb to the sentence, and the correct version becomes clear: “I am just as capable as she is.” (One often hears people saying things like “I am just as capable as her,” but one often hears things said that are not grammatically rigorous.)
Sometimes, the correct choice depends on the meaning of the sentence: Is “She’s more likely to ask him than I” correct, or should you write, “She’s more likely to ask him than me”? If the extended sentence is “She’s more likely to ask him than I am,” in which the comparison is between the subject and the writer, I is correct. However, if the intent is to convey that the man referred to as him is more likely to be asked something by the subject than the writer is, the correct pronoun form is me, but that distinction should be clarified with a revision like “She’s more likely to ask him than ask me.”
Another source of confusion is reflexive pronouns — those that reflect back on the subject. Reflexive pronouns include all the compound words ending in -self (for example, myself) or -selves (for example, themselves). Reflexive pronouns should be used only to refer to another word in the sentence. For example, in “I gave myself a mental pat on the back for a job well done,” myself refers to the subject I. However, in “The letter was intended for myself,” myself has no referent (the subject is “the letter”), so the sentence should read, “The letter was intended for me.”