怎么区分名词从句,定语从句和状语从句?

宾语从句
（一） 宾语从句在复合句中作主句的宾语.宾语从句常由that引导,在口语中常省略. 当主句中谓语动词是现在或将来时态时,从句中谓语动词不受主句中谓语动词时态的 影响,按需要可以使用任何时态.如： She says (that) she works from Monday to Friday. 她说她从周一至周五上班.（从句是一般现在时） She says (that) she will leave a message on his desk. 她说她要在他桌子上留个便条.（从句是一般将来时） She says (that) she has never been to Mount Emei. 她说她从来没有去过峨眉山.（从句是现在完成时） 当主句谓语是过去时态,从句中的时态一般用表示过去的某种时态.如： He said there were no classes yesterday afternoon. 他说昨天下午没有课.（从句是一般过去时） He said (that) he was going to take care of the baby. 他说他会去照看这个婴儿.（从句是过去将来时） He said (that) they were having a meeting at that time. 他说他们那时正在开会.（从句是过去进行时） *当主句谓语是过去时态,而宾语从句叙述某一客观真理（事实）时, 宾语从句的时态则用一般现在时.如： The teacher told us(that) nothing is difficult if you put your heart into it. 老师告诉我们世上无难事只怕有心人. She said (that) her father is twenty-eight years older than her. 她说她父亲比她大二十八岁. He said that light travels much faster than sound. 他说光传播比声音传播快得多. 宾语从句（二） 由连接代词或连接副词引导的宾语从句. 引出名词性从句的连词whether和if,在引出宾语从句时,用法和意义相同.但是只能引出宾语从句和不在句首的主语从句,而whether除了引出宾语从句外,还可引出主语从句、表语从句和同位语从句.例如： We don't know whether (if) it is right. 我们不知道它是否正确. The question is whether she should do that. 问题在于她是否应该做那件事. Whether it is true remains a question. 是真是假还是个问题. 试比较： 当if从句处在主句之后作“是否”讲时,引出的是宾语从句.例如： I don't know if it is true. 我不知道这事是否真实. 当if从句在主句之前作“如果”讲,则引出状语从句.例如： I shall go there if I have time. 如果我有时间,我将到那儿去.
定语从句（Attributive Clauses）在句中做定语,修饰一个名词或代词,被修饰的名词,词组或代词即先行词.定语从句通常出现在先行词之后,由关系词（关系代词或关系副词）引出.
关系代词有：who, whom, whose, that, which等.
关系副词有：when, where, why等.
关系代词所代替的先行词是人或物的名词或代词,并在句中充当主语、宾语、定语等成分.关系代词在定语从句中作主语时,从句谓语动词的人称和数要和先行词保持一致.
1）who, whom, that
这些词代替的先行词是人的名词或代词,在从句中所起作用如下：
Is he the man who/that wants to see you?
他就是你想见的人吗?（who/that在从句中作主语）
He is the man whom/ that I saw yesterday.
他就是我昨天见的那个人.（whom/that在从句中作宾语）
2) Whose 用来指人或物,(只用作定语, 若指物,它还可以同of which互换）, 例如：
They rushed over to help the man whose car had broken down. 那人车坏了,大家都跑过去帮忙.
Please pass me the book whose (of which) cover is green. 请递给我那本绿皮的书.
3）which, that
它们所代替的先行词是事物的名词或代词,在从句中可作主语、宾语等,例如：
A prosperity which / that had never been seen before appears in the countryside. 农村出现了前所未有的繁荣.（which / that在句中作主语）
The package (which / that) you are carrying is about to come unwrapped. 你拿的包快散了.(which / that在句中作宾语）
关系副词可代替的先行词是时间、地点或理由的名词,在从句中作状语.
1）when, where, why
关系副词when, where, why的含义相当于"介词+ which"结构,因此常常和"介词+ which"结构交替使用,例如：
There are occasions when (on which) one must yield. 任何人都有不得不屈服的时候.
Beijing is the place where (in which) I was born. 北京是我的出生地.
Is this the reason why (for which) he refused our offer? 这就是他拒绝我们帮助他的理由吗?
2）that代替关系副词
that可以用于表示时间、地点、方式、理由的名词后取代when, where, why和"介词+ which"引导的定语从句,在口语中that常被省略,例如：
His father died the year (that / when / in which) he was born. 他父亲在他出生那年逝世了.
He is unlikely to find the place (that / where / in which) he lived forty years ago. 他不大可能找到他四十年前居住过的地方.
1.定语从句在句中起到定语的作用；名词性从句在句中起名词的作用,如：主,宾,表,同位.
2.定语从句必须要有先行词；名词性从句则没有.
3.关于that.that在引导定语从句时,在从句中作一定的成分,而在名词性从句中,只起连接的作用,没有实际意义.
英语中从句有三种：状语从句（副词性从句）；定语从句（形容词性从句）；名词性从句（包括主语从句,宾语从句,表语从句和同位语从句）.什么名称的从句即在整个句子中充当什么样的成分.例如：

状语从句：

1.i didn't catch the train because i get up late this morning.(because引导的原因状语从句)
2. if it should rain tomorrow ,we would put off the meeting.(if引导的条件状语从句)
3.As I was wandering in the street, I met her.（as引导的时间状语从句）
4.Where there is a will, there is a way.（where引导的地点状语从句）
5.Although (though) I gave him some advice, he didn’t take them. （although引导的让步状语从句）
6.You should do your homework as i did.（as引导的方式状语从句）
7.Cherry was walking quickly so that (in order that) she could arrived at the cinema in time. （so that 引导的目的状语从句）
8.She is such a nice teacher that all of us love her.（such..that引导的结果状语从句）.
定语从句
是相当于形容词的作用限定修饰名词或代词的.所以定语从句一般是放在名词或代词后面的.（定语从句分限制性定语从句和非限制性定语从句,今天实在没时间打那么多了,改天再细细告诉你两者区分吧）.
1.The man who helped you is Mr White.(who代人,在定语从句中作主语)
2.I´m not the fool(that) you thought me to be.(that代人,在定从中作表语)
3.The house where they live is not very large（where指in the house）
4.This is the reason why he did not came to the meeting. （why引导的从句限定reason）
但不是表时间的先行词都用when引导定从,不是表地点的先行词都用where引导定从.
例如：5.We´ll visit the factory which(＝that) makes radios.
(which或that在定从中作主语,where不可用主语,故不可用)
6.They still remember the happy days(which/that) they spent in Beidaihe.
(which或that在定从中作spent的宾语,when不可作宾语,故不可用)
名词性从句
主语从句用作主语,如：：
That the earth is round is true. 地球为圆的是真实的.
宾语从句用作宾语.如：
Do you know where he lives?
表语从句用作表语,如：
My opinion is that you should not go alone. 我的意见是你不应单独前往.
同位语从句用于解释说明前面的名词.如：
The fact that the earth is round is true. 地球是圆的的事实是真实的.（that从句用于解释说明the fact）
不知对你有帮助没?如果还有什么疑问尽管提.我会尽力的来解释清楚追问我的疑点是怎么区分他们啊?分析一个句子看起来也像宾从、状从、同位从（差不多这个意思）如你写的这个句子：Do you know where he lives? where为什么不是引导的地点状语从句?This is the reason why he did not came to the meeting.why为什么不是引导的同位语从句、原因状语从句?解释说明the reason抽象名词啊就像所有的抽象名词并不一定是同位从,我该怎么区别啊?My opinion is that 这个我知道是表从去了is同位从吗?
回答应为这里where跟在konw后是做他的宾语,她主要充当的是个宾语的成分,而你感觉它像在说地方,那只是它表达的意思,而判断它的成分主要看他在整个句子中的用法.它并没有做地点状语修饰哪个词,不信你自己仔细看看,它只是做宾语
宾语从句：在句子中起宾语作用,如：I konw that he has returned. 其中that he has returned作为宾语来用,为宾语从句.
状语从句：起副词作用,分为时间、地点、原因、条件、目的、结果、让步、方式和比较等.
定语从句：用作修饰主句的某个名词性成分,相当于形容词,又叫形容词性从句,一般紧跟在它所修饰的先行词后面,如：I konw the reason why he was so angry.如果将why he was so angry去掉,原句主句部分仍可成句.
表语从句：多接在be动词后面,用来说明主语,如：The question is how he did it.