"HE AND I" or "HIM AND ME"?
WHO vs. WHOM:
Even though nowadays, in casual conversation or dialogue in novels, “whom” often seems affected or pretentious and out of place, it’s good to know the correct usage for nonfiction writing, academic writing, journalistic writing, some narration, and dialogue spoken by educated characters.
Here’s the general rule:
Who is used for the subject of a verb or the doer of the action: “Who saw him?”
Whom is correct for the object of the verb, or the receiver of the action: “Whom did he see?”
Whom is correct usage after prepositions (by, for, to, with before, after, beside, in front of, etc.), e.g., By whom? For whom? With whom? To whom? “To whom are you referring?” “The woman for whom he gave his life.”
Quick trick: A quick way to remember which to use: Ask yourself whether the answer would be “he” or “him”. If he, use who, if him, use whom. Who went with you? He went with me. Whom did you see? I saw him.
Is it “Whom should I say is calling?” or “Who should I say is calling?”
(He is calling, so “who” is correct here.)
Is it “Who will you choose to go first?” or “Whom will you choose to go first?”
(You’ll choose him, so “whom” is correct here.)
As I mentioned, the use of “whom” in everyday conversation often seems somewhat affected these days. So, unless you want to come off as sounding pedantic, it’s best to avoid using “whom” in casual conversation with friends or family. Also, avoid whom in casual dialogue in fiction, especially (obviously!) when rough or uneducated people are talking!
“which” always follows a comma, while “that” almost never follows a comma.
“Style Blunders in Fiction”
“Hyphens, Dashes, Ellipses.”