英语语法：202 Who Versus Whom

Today's topic is who versus¹ whom.  I've received three requests from listeners to cover this topic. Here's Noreen:
I just wondered if possibly in one of your episodes you could go through the use of who versus whom. I think that's a common misunderstanding with many people who write.
And an unnamed caller:
Who and whom: that's always a tough one.

And then Jen also asked in an e-mail.
Who or Whom?
So here we go. The words who and whom are both pronouns. I'll have a quick and dirty trick for you later, but first I want you to actually understand the right way to use these words.

First, to know whether to use who or whom, we need to talk about the difference between subjects and objects because you use who when you are referring to the subject of a clause and whom when you are referring to the object of a clause.

I know: subject and object sound pretty abstract, but it's easy. If we think about people, the subject of the sentence is the person doing something, and the object of the sentence is having something done to them. If I step on Squiggly, then I am the subject and Squiggly is the object.

Still having a hard time remembering? Here's my favorite mnemonic: If I say, "I love you," you are the object of my affection, and you is also the object of the sentence (because I am loving you, making me the subject and you the object). How's that? I love you. You are the object of my affection and my sentence.  It's like a Valentine's Day card and grammar mnemonic all rolled into one. 
Just Whom
OK. So you all asked about who versus whom, but what I think you really want to know is just when to use whom, because most people don't go around throwing unneeded whoms into their sentences. So remember, you use whom when you are referring to the object of a sentence. Use whom when you are referring to the object of a sentence.

For example, it is "Whom did you step on?" if you are trying to figure out that I had squished Squiggly. Similarly, it would be "Whom do I love?" because you are asking about the object -- the target of my love. I know, it's shocking, but the Rolling Stones were being grammatically incorrect when they belted out the song "Who Do You Love?" which I think was originally written by Bo Diddley.
Just Who
So when is it OK to use who? If you were asking about the subject of these sentences, then you would use who. For example, "Who loves you?" and "Who stepped on Squiggly?" In both these cases the one you are asking about is the subject -- the one taking action, not the one being acted upon.
A Quick and Dirty Tip
Still too hard to remember? OK, here's the quick and dirty tip. Like whom, the pronoun him ends with m. When you're trying to decide whether to use who or whom, ask yourself if the answer to the question would be he or him. That's the trick: if you can answer the question being asked with him, then use whom, and it's easy to remember because they both end with m. For example, if you're trying to ask, "Who (or whom) do you love?" The answer would be "I love him." Him ends with an m, so you know to use whom. But if you are trying to ask, "Who (or whom) stepped on Squiggly?" the answer would be "He stepped on Squiggly." There's no m, so you know to use who. So that's the quick and dirty trick: if you can't remember that you use whom when you are referring to the object of the sentence, just remember that him equals whom.
Diversions
 

1 versus   

prep.以…为对手，对；与…相比之下

参考例句：

• The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
• The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。