有一位读者来信问道：who 在什么情况下可以代替 whom？
关于这个问题，许多年来，一直都是有争议的。我们的初步看法是：作为疑问代词，在非正式英语中，主格 who 确是常可代替宾格 whom，例如：
(1)Who do you trust?
(2)Who are you looking for?
who 也可在间接疑问句中代替 whom， 例如：
(3)It depends on who you want.
who 也可置于及物动词之前，例如：
(4)—I saw Ted Dawson today.
—You saw who ? （有人说大多数人仍用 whom）
who 也可置于不定式之前，例如：
(5)Learn who to trust and who not to trust, but don't really trust anyone to start off with.
who 甚至有时还可置于介词之后，例如：
(6)—I give it away.
—To who . （但仍须说 To whom did you give to?）
但在正式英语中，尤其在正式书面语中，许多语法家认为疑问代词 whom 还是不被 who 代替的好。
who 与 whom 用作关系代词时，在非正式英语中，whom 也常被 who 所代替，例如：
(7)The man who I bought it from told me to oil it.
(8)The man who I saw is called Smith.
(9)The people who you were talking to are Swedes.
(10)Mr. Dantry, who I found in great shape and still as dynamic as in the past, asked me to write a note on the mission of March 1940.
为什么主格 who 可以代替宾格 whom 呢？ 其原因并不复杂。由上述例句可以看出， who 所占有的位置是一句之首或一从句之首， 而这正是主语的正常位置，而主语的位置应为主格 who 所占有，这一错觉就是 who 可代替 whom 的原因所在。
但请注意，在复合定语从句中，who 与 whom 却都被认为是正确而且自然的英语。用 who 的情况有如：
(11)I met a man who I thought was a lunatic.
(12)There is no one who we can believe is competent.
有的语法家认为 who 之后应有停顿（或一逗号），如：
(13)There was one， who , I learned it after days, was seen expiating some maturer offence in the hulks.
用 whom 的情况似乎更不鲜见。之所以可以用 whom， 显然是受到其后的及物动词的影响的缘故。但有的较保守的语法家认为用 whom 是错误的，应代之以 who。注意 whom 之后一般不停顿（或不用逗号），例如：
(14)A woman whom I knew was my friend spoke next.
(15)There I saw an old woman whom I guessed was his mother.
(16)The school, founded by the 300 residents of the village, has enrolled 40 children whom they hope will be future soccer stars.
(17)We would welcome your personal recommendation of friends and colleagues whom you consider merit inclusion in Dictionary of International Biography.
whom 有时则难以说是与其后的及物动词有任何关系， 例如：
(18)My wife whom I thank heaven is an honest woman.
(19)He instructed Chang to arrest the Kuomintang agents whom Han had told him were hiding in the village.
最后，我们认为，对中国学生来说，在没有把握的情况下，还是按语法和教科书的规定办事为好。
