who are you whom are you?的区别

我们老师说现在简化了.只要学who的用法
（1）正式用法中, who 是主格 （subject pronoun）,在句子中作主语（subject)、或在从句中作主词的补语（the predicate pronouns of their own clauses）. 例如:
例句-1: We will give the money to the person who needs it most.
在上面的例句-1 中 who 是动词 needs 的主语.
例句-2: No one knows who you are.
在上面的例句中 who 是 从句 who you are 的补语. 用英语说就是："who" is the predicate pronoun of the clause "who you are."以前讲过, 联系动词的前后都是名词（或代词）时,它们是指同一件事, 所以 you = who.
（2）正式用法中, whom 是受格（object pronoun）, 在句子中作及物动词的宾语（object）或介词的宾语.请看以下的例句：

例句-3: We filed a complaint against the contractor whom we hired last month.
在从句 whom we hired last month 中,we 是主语, hired 是谓语（及物动词）,whom 是及物动词 hired 的宾语.
例句-4: To whom does this book belong?
这里 whom 作 介词 to 的宾语（object）
（3）口语或非正式用法中,作动词或介词的宾语的 whom 放在句首时,往往被 who 所代替.如果 whom 紧接在介词之后, 如 例句-4, 则不可被 who 代替.
例句-5: Who (or Whom) do you take her to be?
这个句子可译为：你以为她是谁?
例句-6: Who (or Whom) is this letter from?
这个句子可译为：这封信是谁寄来的?
例句-7: Who (or Whom) did you invite to the party?
（4）引导定语从句时,whom 一般被 who 或 that 代替.
例句-8: The man (who/that/whom) I met in San Jose was very kind