关系副词的概念：

关系副词兼有副词与连接词两种作用，在不及物动词的连接中要求用关系副词。关系副词有when, where, why。

关系副词的特点：

关于副词用于引出定语从句，主要有when, where, why：
如：Sunday is the day when very few people go to work. 星期日是没什么人上班的日子。 
        That's the reason why he dislikes me. 这就是他不喜欢我的原因。 
        Do you know a shop where I can find sandals? 你知道哪家商店我能找到凉鞋吗？
注：关系副词用于引出定语从句，且在从句中用作状语。关系副词when表示时间，where表示地点，why表示原因。

使用关系副词应注意的几点：

（1）how不能用作关系副词，不要想当然地将how用作关系副词置于theway后表示方式：他说话就是那个样子。
误：This is the way how he spoke.
正：This is how he spoke./ This is the way（that, in which）he spoke.
（2）关系副词when和where既可引导限制性定语从句，也可引导非限制性定语从句，但why只能引导限制性定语从句，不能引导非限制性定语从句（若引导非限制性定语从句，可用for which reason）。
（3）引导定语从句时，when的先行词为时间，where的先行词为地点，why的先行词为原因（主要是the reason），但是反过来却不一定：
如：Don't forget the time(that) I've toldyou.不要忘记我告诉你的时间。
        Do you know the house(that) he bought recently? 你知道他最近买的那座房子吗？
        Please tell me there as on(that) you know. 请告诉我你所知道的原因吧。

关系副词的用法：

关系副词有when, where, why，作用有三个：
1、连接主句与从句；
2、代替先行词；
3、在从句中作状语，不可省略。
When和where既可引导限制性定语从句，也可引导非限制性定语从句。Why只能引导限制性定语从句。这些关系副词在意义上都相当于一定得“介词+which”结构。
1）when=at/in/on/during，在定语从句中作时间状语。
例如：Tell me the time when(at which) the train leaves.
注意：
①当表示时间的先行词在从句中中作主语或宾语时，不能用when。
例如：I will never forget the days I spent with your family. 
②It/This/That+be+the first/second/last time that…句型中，that是习惯用法，不能用 when代替，that还可以省略。从句中使用与“be动词”呼应的完成形式。
例如：It is the first time that I have been to the Great Wall.
2）where表地点，只能跟在表示地点的名词后，它在定语从句中作地点状语。
例如：This is the second school where I used to teach.
注意：
①引导词where可用that替换，并经常可以省略。
例如：That's the place(where/that) we went before.
②当表示地点的先行词在句中作主语或宾语时，不用where，用关系代词that或which。
例如：The factory that/which we visited yesterday was built last year.
③where可与from连用。
例如：His head soon appeared out of the second story windows, from where he could see nothing but rees.
3）why表原因，引导的从句修饰名词reason。Why可用that或forwhich替换或省略。
例如：I don't know the reason(why/for which/that) he left here.

状语从句的概念：

状语从句指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。状语从句一般由连词(从属连词)引导，也可以由词组引起。从句位于句首或句中时通常用逗号与主句隔开，位于句尾时可以不用逗号隔开。

比较while/as/when：

1、as/when引导短暂性动作的动词例句：
如：Just as/Just when/When I stopped my car, a man came up to me.
2、当从句的动作发生于主句动作之前，只能用when引导这个从句，不可用as或while。
如：When you have finished your work, you may have a rest.
3、从句表示“随时间推移”连词能用as，不用when或while。
如：As the day went on, the weather got worse.

比较untill/till：

两个连词意义相同,肯定形式表示的意思是“做某事直至某时”，动词必须是延续性的。否定形式表达的意思是“直至某时才做某事”，动词为延续性或非延续性都可以。
正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。
肯定句例句：I slept until midnight. 我一直睡到半夜时醒了。
                       Wait till I call you. 等着我叫你。
注意：在肯定句中可用before代替：Let's get in the wheat before the sunsets.
否定句例句：She didn't arrive until 6o'clock. 
                        I didn't manage to do it until you had explained how.
1、Until可用于句首，而till通常不用于句首。
例句：Until you told me, I had heard nothing of what happened.
2、Untilwhen疑问句中，until要放在句首。
例句：Until when are you staying? 你呆到什么时候？
注意：否定句可用另外两种句式表示。
1）Not until…在句首，主句用倒装。
例句：Not until the early years of the19th century did man know what heat is.
2）It is not until…that…

状语从句的用种类：

1、时间状语从句：
表示时间的状语从句可由when, as, while, whenever, after, before, till(until), since, once, as soon as(或the moment), by the time, no sooner…than, hardly(scarcely)… when, everytime等引导。 　　
e.g. When I came into the office, the teachers were having a meeting. 　　
       He started as soon as he received the news. 　　
       Once you see him, you will never forget him. 　　
       No sooner had I gone to bed than I went to sleep. 　　
2、原因状语从句：
原因状语从句是表示原因或理由的，引导这类从句的最常用的连词是because, since, as, nowthat（既然）等，for表示因果关系时（它引导的不是从句）为并列连词，语气不如because强。 　　e.g. He is disappointed because he didn't get the position. 　　
      As it is raining, I will not go out. 　　
      Now that you mention it, I do remember. 　　
3、地点状语从句： 　　
引导地点状语从句的连词是where和wherever等。 　　
e.g. Sit wherever you like. 　　
      Make a mark where you have a question. 　　
4、目的状语从句： 　　
引导目的状语从句最常用的词（组）是so, so that（从句谓语常有情态动词）, in order that, in case（以防，以免）等。 　　
e.g. Speak clearly, so that they may understand you. 　　
      She has bought the book in order that she could follow the TV lessons. 　　
      He left early in case he should miss the train. 　　
5、结果状语从句： 　　
结果状语从句是表示事态结果的从句，通常主句是原因，从句是结果。由so that（从句谓语一般没有情态动词）,so…that, such…that等引导。 　　
e.g. She was ill, so that she didn't attend the meeting. 　　
      He was so excited that he could not say a word. 　　
      She is such a good teacher that everyone admires her. 　　
6、条件状语从句： 　　
条件状语从句分真实性（有可能实现的事情）与非真实性（条件与事实相反或者在说话者看来不大可能实现的事情）条件句。
引导条件状语从句的词（组）主要有if, unless, so(as)long as, on condition that, so(as) far as, if only(=if)。
注意：条件从句中的if不能用whether替换。 　　
e.g. If he is not in the office, he must be out for lunch. 　　
      You may borrow the book so long as you keep it clean. 　　
      So far as I know（据我所知）, he will be away for three months. 　　
      You can go swimming on condition that(=if) you don't go too far away from the river bank. 　　
      If he had come a few minutes earlier, he could have seen her. 　
7、让步状语从句： 　　
让步状语从句可由although, though, as, even if(though), however, whatever, whether…or, no matter who(when, what,…)等引导。
注意：as引导的让步状语从句一般是倒装的。 　　
e.g. Though he is a child, he knows a lot. 　　
      Child a she is, he knows a lot. 　　
      Whatever(=No matter what) you say, I'll never change my mind. 　　
8、方式状语从句： 　　
方式状语从句常由as, as if(though), the way, rather than等引导。 　　
e.g.You must do the exercise as I show you. 　　
      He acted as if nothing had happened. 　　
9、比较状语从句： 　　
比较状语从句常用than, so(as)…as, the more…the more等引导。 　　
e.g. I have made a lot more mistakes than you have. 　　
      He smokes cigarettes as expensive as he can afford. 　　
      The busier he is, the happier he feels.

使用状语从句时要注意的几个问题：　　

1、在时间和条件（有时也在方式、让步等）从句中，主句是一般将来时，从句通常用一般现在时表示将来。　　
e.g. We'll go outing if it doesn't rain tomorrow. 　　
       I'll write to you as soon as I get to Shanghai. 　　
2、有些时间、地点、条件、方式或让步从句，如果从句的主语与主句主语一致（或虽不一致，是it），从句的谓语又包含动词be，就可省略从句中的“主语+be”部分。　　
e.g. When(hewas) still a boy of ten, he had to work day and night. 　　
       If(you are) asked you may come in. 　　
       If(it is) necessary I'll explain to you again. 　　
3、注意区分不同从句：引导的是什么从句，不仅要根据连词，还要根据句子结构和句意来判别。以where为例，能引导多种从句。　　
e.g. You are to find it where you left it.（地点状语从句）　　
       Tell me the address where he lives.（定语从句，句中有先行词）　　
       I don't know where he came from.（宾语从句）　　
      Where he has gone is not known yet.（主语从句）　　
       This place is where they once hid.（表语从句）
注意：表示“一…就…”的结构 hardly/scarcely…when/before/no sooner…than和as soon as都可以表示“一…就…”的意思。
例句：I had hardly/scarcely got home when it began to rain.
            I had no sooner got home than it began to rain.
           As soon as I got home, it began to rain.
注意：如果hardly/scarcely或nosooner置于句首，句子必须用倒装结构：
例句：Hardly/Scarcely had I got home when it began to rain.
            No sooner had I got home than it began to rain.

非限制性定语从句的概念：

非限制性定语是对被修饰名词或代词的附加说明，它不是必需的，如果去掉，也不会影响句子的意思，它与被修饰名词之间通常用逗号分开。
如：The travellers, knowing about the floods, took another road. 游客们知道发了大水，都改道走了。
        The boys, wanting to play football, were disappointed when it rained. 那些男孩子想踢足球，因为下雨感到失望。

非限制性定语从句用法：

1、引导非限定性定语从句时，只能用which(不用that)。
例如：Heat is another form of energy, which is as important as other kinds of energy.
            热是另一种形式的能量，与其他形式的能量一样重要。 （从句表补充说明，而且关系代词which不能换成that。） 　　
2、引导非限定性定语从句的which可以指代前面的先行词,也可以指前面整个句子的含义。
例如：That Peter will marry Alice, which has not been announced yet, has spread around.
            彼特要娶爱丽斯这件事还没宣布，却已传得沸沸扬扬。（句子中的which指“彼特要娶爱丽斯”这整个句子的意思。） 　　
3、除which外，还可用when，where，who等关系代、副词引导非限定性定语从句。
例如：After graduation, I decided to stay in Chongqing, where I spent my childhood and four years of college life. 
毕业后，我决定留在重庆，在那里我曾度过了我的童年和四年大学生活。 　　                 
Albert Einstein left Germany for the United States during World WarII, when Jews were badly treated in Germany.  
第二次世界大战期间，爱因斯坦离开德国去了美国，那时犹太人在德国受到不好的对待。 　　
4、在限定性定语从句中作宾语时，引导词可以省略，但引导非限定性定语从句的关联词不能省。
如：He was eager to go to the hospital to see his stepmother, whom he loved and respected as his own mother. 
他急于想去医院看望他的继母，他把他的继母当作亲生母亲一样热爱和尊敬。 　　    
The American journalist(whom/who) the announcer mentioned in the news broadcast is said to have been killed by the gangsters.
 播音员在新闻广播中提到的那位美国记者据说已经被匪徒杀害了。 　　
两例中的关系代词都在从句中作宾语。由于第二例是限定性定语从句，可以省略关系代词；第一例中的引导词不能省略，因为它引导的是非限定性定语从句。 　　
5、表示“正如”的含义时，通常用as引导非限定性定语从句，也可用which引导；但置于句首时，只能用as引导。 　　
如：China has basically succeeded in defeating SARS, which/as we have expected.
        正如我们所预料的那样，中国已基本上战胜了“非典”。 　　  
        As is well known to everybody, Tai wan is an inseparable part of China.
        众所周知，台湾是中国不可分割的一部分。 　　
但是当非限定性定语从句是否定含义时，就只能用which(而不用as)引导。
如：He didn't win the championship, which I hadn't expected.
        他没获得冠军，这一点是我没预料到的。

非限制性定语丛句中as, which的区别：

1、which引导非限制性定语丛句代表前面的整个句子的时候，一般是对主句的结果的说明。 
      如： He grows too fast, which makes him taller than his classmates.
2、as引导非限制性丛句代表前面整个句子时一般来讲丛句的谓语动词有三种：
A. 含有be动词：
如：He failed the exam, as is natural.
B. 实意动词的被动形式：
如：As is reported, the fire caused a great loss.
C.感官动词和意识类动词如：
如：see, hear, notice, know, learn, realize 等。 
        As you know, I am a teacher.
3、as可翻译为正如，它引导的丛句可位于主句之前，也可位于主句之后；which引导的该丛句只能位于主句之后。
例1：__A___he realized, I was very useful to him. 
例2：This elephant is like a snake, ___A__anybody can see. 
例3：The sun gives us light and heat, __B___makes the plan tgrow well.
          A. As(as)
          B. which
          C. that
          D. who

限定性定语从句与非限定性定语从句的区别：

非限制性定语从句的关系词：

非限定性定语从句的使用规则及注意事项：

1、which引导的非限定性定语从句是用来说明前面整个句子的情况或主句的某一部分。
2、在引导限定性定语从句时，that有时相当于in which, at which, for which或at which。其中，介词的选用，依据从句中的动词所需搭配的介词来选用。例句：
① Attitudes towards day dreaming are changing in much the same way that(inwhich)attitudes towards night dreaming have changed.
    人们对白日做梦的态度正在改变，这与人们对夜间做梦的看法的变化有非常相似之处。
② I like the music for the very reason that(for which) he dislike it. 
    我出于某种原因喜欢这种音乐，而他恰恰与我相反。
③ We arrived the day that(on which) they left.
    刚好我们到的那天他们走了。
3、as有时也可用作关系代词。
4、在非限定性定语从句中，关系词不能用that。