I and me are personal pronouns, which are commonly confused in speech and writing. Here are the correct ways to use them.
When to Use I
I is a subjective pronoun, meaning that it should be used in the subject of a sentence. The subject is whoever is doing the action. If you are doing something, you would say “I am doing something.”
An easy way to tell if you are looking at the subject of the sentence and should use I is to try to substitute other pronouns. Any time you could use the pronouns we, you, she, he, or they you are looking at the subject of a sentence. If you can substitute any of these pronouns in place of the personal pronoun, you should be using I rather than me.
I wanted more cake.
If you were unsure if I was correct, you could try to use she instead.
She wanted more cake.
Because she fits correctly, you would know that I is the right pronoun.
When to Use Me
Me is used in the object of a sentence or after a preposition. The object of the sentence is whoever or whatever is receiving the action of the verb. “The duck followed me at the park.” The speaker in this last sentence is the one who is being followed, so we know that he or she is the object of the verb follow. Because the speaker is the object of the sentence, an objective pronoun will be used, meaning me.
Just like with I, you can substitute other objective pronouns if you are unsure whether to use I or me. These pronouns include her, him, you, and them.
Jane talked to them.
In this case, because you could use them as a correct pronoun, you know you should use me.
Jane talked to me.
Most people confuse I and me when using two nouns in the subject or object. “John and I went to the store.” In this case, “John and I” is the subject of the sentence because “John and I” are the ones who went to the store. Because this is the subject, you need to use I. “The baby went to the park with John and me.” Because the baby is the one who went to the park, you know that “John and me” is not the subject, so you use me.
The easiest way to test whether you should use I or me when dealing with two nouns is to remove the extra noun and see if the sentence is still correct.
John and I saw a movie.
If you remove John, the sentence is correct if you say “I saw a movie.” It is not correct if you say “Me saw a movie.” This means that you should use the subjective pronoun I when you use both nouns in this sentence.
Who or Whom
The case of who or whom is the same as I and me. Who is the subjective case, like I, while whom is the objective case and also follows prepositions. This rule applies whether these words are used in questions or in order to add extra information in a sentence, meaning as a relative pronoun.
Who is going to the movie?
I am going to the movie with whom?
Whom Who do you think is the prettiest? The easiest way to determine the correct usage in a question is to rephrase the sentence into a statement. Instead of “Whom do you think is prettiest,” you could rephrase the sentence into, “You think Sarah is the prettiest.” By rephrasing, it becomes clear that you are the one doing the thinking, so the object is the person you think is prettiest, meaning that you should use whom.
A reader correctly pointed out that the usage of whom in the above example is incorrect. “Do you think,” in the above example is a parenthetical phrase, meaning a phrase that is not essential to understanding the meaning of the rest of the sentence.
Because parenthetical phrases may be removed without changing the meaning of, you may ignore those parts of sentences when deciding whether Who or whom should be used.
In this case, when we remove the parenthetical phrase, the sentence becomes “Who/m is the prettiest.” Because this could be rephrased as “She is the prettiest,” rather than “Her is the prettiest,” we know that the subjective case Who is correct.
Thanks to our reader who not only caught my mistake and taught us a lesson in parentheticals, but also proves that Who and Whom can be confusing for everyone.
In the case of relative pronouns, it can be more difficult to define whether the pronoun is the subject or object.
The girl, who wore a red dress at the party, is coming to dinner.
Because the girl wore the red dress, the clause is subjective, so who is correct.
Jill, whom you met last week, is coming to the party.
In this case, you were the one who met Jill, so the clause is objective, meaning that whom is correct.
To determine the correct form when using relative pronouns, break the sentence down into smaller sections. “Who wore the red dress at the party?” could be rephrased into, “She wore the red dress at the party,” so you should use a subjective pronoun. “You met whom last week?” can be “You met her last week,” so you use the objective whom.