How do you decide which form of a pronoun to use, as in the choices of the wording in “John is as fast as him” and “John is as fast as he”? Knowing the varieties of pronouns will help you choose the correct form.
A subject pronoun is one used as the subject of a sentence, as in “He is right” or “I am amazed.” (Subject pronouns include I, you, he, she, it, we, and they.) Subject pronouns may also rename the subject, following a linking verb (one that is a form of “to be”): “It is I who left the chair there.”
A subject pronoun should also be used for such sentences as “It might have been she,” though an object pronoun is used in its place almost invariably in casual speech and often in writing.
Object pronouns (me, you, him, her, it, us, and them), by contrast, are used to identify the object of a sentence, as in “Mary gave it to her” and “The tourists went to see them.” (Notice that you and it can serve as both subject and object pronouns.) Object nouns are used with all the three types of objects: “The Smiths invited us” (direct object), “The Smiths gave us our dish back” (indirect object), and “The Smiths gave a party for us” (object of a preposition). “Joe and I were invited to the party” is correct because I is part of the subject (“Joe and I”). But “John went to the party with Joe and I” is not, because “Joe and I” is now the object, and the correct personal pronoun for an object is me: “John went to the party with Joe and me.” (Test for the correct form of the pronoun by removing the other person from the object: “John went to the party with me,” not “John went to the party with I,” is correct, so “John went to the party with Joe and me” is correct.)
But an exception is made when the reference to Joe and the writer is preceded by a copular, or linking, verb (a form of “to be”), as in “The last people at the party were Joe and I.” In this sentence, “Joe and I” are predicate nominatives, meaning that they