whom的用法定语从句
  whom的用法定语从句：
  whom主要用在当先行词表人的情况下，在从句中充当动词或介词的宾语。如：
  The boy whom you met on the street just now is one of cousins.
  He is the man from whom you ought to ask for help.
  whom也可以用来引导非限定性定语从句。如：
  The soldiers, some of whom come from Alaska, will be sent to Iraq next week.
  英语定语从句的用法
windows me  （一）whose
  whose是所有格形式，所以在引导定语从句时，后面会紧跟一个名词。其先行词既可能是人，也可能是物。如：
  The boy whose father is a professor studies very hard.
  Are there any rooms whose windows face the sea?
  whose也可以用来引导非限定性定语从句。如：
  I decided to write about Chaplin, whose films are still very popular among a large audience.
  （二）which的用法
  which用来引导定语从句时，其先行词都是表物的。如：
  非限定性定语从句：He sent me five books, which helped me a lot in my English exam.
  限定性定语从句：This is the ship which I travelled on two months ago.
  第一句中的which helped me a lot in my Englsh exam作为five books的非限定性定语从句，补充说明了这五本书对我英语考试的帮助。
  第二句中的which I travelled on two months ago作为the ship的限定性定语从句，特指这艘轮船是我两个月前乘坐的那艘。
  【注意】
  1、当which在从句中作宾语时，往往可以省略。比如上面的限定性定语从句中的which就可以省略，即：
  This is the ship I travelled on two months ago.
  但是，当which前面有介词时，就不能省略。比如上面这句话就可以改为：
  This is the ship on which I travelled two months ago.
  2、as与which的区别
  as和which都可以用来引导定语从句，而且可以指代整个主句。但是，两者在用法上存在一定差别。
  1）两者都可以在定语从句中做主语或者宾语，代表前面整个句子。如：
  They love each other, as/which is natural.
  He doesn't like it, as/which we can see.
  2）as有“正如或正像”的意思，其引导的非限制性定语从句，位置可在句首、句末或句中。which引导的非限制性定语从句只能放在主句之后。如：
  As is known to all, man cannot live without air. / Man cannot live without air, as is known to all. / Man, as is known to all, cannot live without air.
  It is said that he can type 200 words within one minute, which I don't believe.
  3）当主从句是因果关系时，一般都用which。如：
  He is always complaining about everyting, which annoys everyone around him.
  4）如果先行词中含有such或the same时，则用as。如：
  He is not such a fool as he looks.
  This is the same book as she lost yesterday.
  需要注意的'是：当先行词含有the same时，偶尔也用that来引导定语从句，这时与as引导的定语从句意思是不一样的。如：
  She wore the same dress that she wore at Mary's wedding. （她穿着她在Mary婚礼上穿过的一条裙子。）
  She wore the same dress as her young sister wore. （她穿着和她妹妹所穿的一样的裙子。）
  （三）who
  who主要用在当先行词表人的情况下，一般在从句中充当主语，但有时也可以作宾语，相当于whom。如：
  He's the man who bought these books just now.
  The man who I served was wearing a hat.
  第一句中的who在从句中作bought的主语，而第二句中的who则作served的宾语。
  需要注意的是，当介词位于定语从句的句首时，就不能用who，而要用whom。如：
  She is the girl about whom the man talked at the meeting an hour ago.
  who也可以用来引导非限定性定语从句。如：
  The manager, who comes from Japan, told me to help you with your project.
  （四）whom
  whom主要用在当先行词表人的情况下，在从句中充当动词或介词的宾语。如：
  The boy whom you met on the street just now is one of cousins.
  He is the man from whom you ought to ask for help.
  whom也可以用来引导非限定性定语从句。如：
  The soldiers, some of whom come from Alaska, will be sent to Iraq next week.