两者均只用于人，从理论上说，who 为主格，whom为宾格，但实际上，除非在正式文体中，宾格关系代词 whom 往往省略不用，或用who或that代之。如：
The man (that, who, whom) you met just now is called Jim. 你刚遇见的那个人叫吉姆。
不过，值得注意的是，直接跟在介词后面作宾语时，只能用 whom，而且不能省略。如：
She brought with her three friends, none of whom I had ever met before. 她带了3个朋友来，我以前都没见过。
另外，引导非限制性定语从句且作宾语时，who 和 whom均可用，但以用 whom 为佳，此时也不能省略。如：
This is Jack, who [whom] you haven’t met before. 这是杰克，你以前没见过。
单词：whom的近义词、反义词、形近词辨析
who/whom
Who are you trying to fool?你想愚弄谁呀？
To whom is she writing?她在给谁写信。
<辨的>who 与 whom 都可作疑问代词，who 是主格，whom 是宾格。如：
Who saw the thief?谁看见了那个贼？
在日常口语中，常用 who 代替 whom 用作宾格（如开头提到的第一个例句），但是 who 不能直接用在介词后，这时，必须用 whom（如开头提到的第二个例句）。
与单词：whom 相关的例句或者名人名言
Do you know whom the reporters are discussing?
你知道记者在讨论谁吗？
The wife of Orpheus, whom he failed to rescue from Hades when he looked back at her and so violated the command of Pluto on their journey back to the upper world of the living.
欧律狄刻俄耳甫斯的妻子，没能被丈夫救出地狱，因为他们在走出冥界之前他回头看了妻子，违反了冥王的规定
To whom shall I debit the amount?
这笔帐要记入谁的借方帐中?
The bare loss of him as a gullant was not so much my affliction as the loss of his person, whom indeed I loved to distraction.
