2. such ... as
　　1) as在从句中作主语
　　Let children read such books as tend to make them better and brighter. 让孩子看那些容易让他们变得更好更聪明的书。
　　2) as在从句中作宾语
　　This is not such an interesting book as you just talked about. 这不是你们刚才谈到的那种有趣的书。
　　3) as在从句中作be动词的表语
　　Such a bad man as he is will be punished. 像他这样的坏人一定会受到惩罚。
3. as ... as
　　1) 第二个as在从句中作主语
　　He has as much money as is required. 他要多少钱就有多少钱。
　　2) 第二个as在从句中作宾语
　　I have as many friends as you (do). 我的朋友和你的朋友一样多。
　　3) 第二个as在从句中作be动词的表语
　　As is known to all, Taiwan is one of the Chinese provinces。众所周知,台湾是中国的一个省。

二、than作为准关系词 出现在more ... than, less ... than, fewer ... than等结构中。这时, than前面要有名词; than本身有比较意义,而且需要在从句中充当一定的句子成分。
　　1. than在从句中作主语
　　Take it easy, I have more money than is needed. 放心，我的钱比所需要的还要多。
　　2. than在从句中作宾语
　　I have more/fewer books than you (do). 我的书比你的多/少。
　　3. than在从句中作be动词的表语
　　He is a better boy than you (are). 他是一个比你更好的男孩。
三、but作为准关系词 本身含有否定意义,它前面的主句还有另一个否定意义。这时but在意义上相当于“who ... not ...”或“which/that ... not ...”。
　　1.定语从句中有be动词,并将其改为含but的复合句时, be动词后面不能再有not
　　There is no one who is not conccrned about his future. (= There is no one but is concerned about his future.) 没有人不关心自己的未来?
　　2. 定语从句中有can, will, shall, must, may, should, ought to等助动词或情态动词,在将其改为含but的复合句时,这些助动词或情态动词后面不能再有not
　　There is nothing that she can’t do. (= There is nothing but she can do.) 没有她做不到的事?
　　3. 定语从句中有助动词do, does, did, 在将其改为含but的复合句时,应去掉do, does, did, 还原其后动词的时态及人称变化
　　There is no one who doesn’t wish to make great achievements. (= There is no one but wishes to make great achievements.) 谁都希望自己将来能有所成就。
四、which的先行词：关系代词which的先行词可以是一个句子
　　He said he saw me there, which was a lie。他说在那儿看到了我，纯属谎言。
说明：关系代词that在从句中作宾语或表语时可省略
　　I've forgotten much of the Latin I once knew。 我过去懂拉丁语，现在大都忘了。  

考点名称：宾语从句

• 宾语从句：
  在句子中起宾语作用的从句叫做宾语从句。
  宾语从句分为三类：动词的宾语从句，介词的宾语从句和形容词的宾语从句。
  宾语从句连接代词主要有：
  who, whom ,whose ,what ,whoever ,whomever ,whosever, whatever, whichever 等。

• 宾语从句的特点:
  1.宾语从句可以作及物动词、介词及形容词的宾语。
  2.宾语从句的语序一律用陈述句语序。
  3.连接词that引导宾语从句在句中无词义，不充当句子成份，多数情况下可以省略。
  4.whether 和 if 都可引导宾语从句，但 whether后可紧跟or not；whether从句可作介词的宾语。
  5.如果从句太长，可以用形式宾语it.

  宾语从句的时态:
  1.主句是一般现在时，从句根据实际情况使用任何时态。
  例句：The headmaster hopes everything goes well.
  2.主句是过去时态，从句须用过去时态的某种形式。
  例句：She was sorry that she hadn’t finished her work on time.
  3.当宾语从句表示的是一个客观真理或者事实时，即使主句是过去时，从句也用一般现在时态。
  例句：The teacher told his class that light travels faster than sound.
  4. 如果从句的动作发生在主句之前，则从句要用过去完成时态。 
  
  宾语从句的语序:
  A. 宾语从句必须用陈述语序。 　　
  False: He is wondering when can he finish this difficult job. 　　
  Right: He is wondering when he can finish this difficult job.
  B. 有时候可以用it 作形式宾语，而把真正的宾语从句放在后面。 　　　
  Bad: I thought that he could finish this　job in just two hours impossible. 　　
  Good: I thought it impossible that he could finish this job in just two hours.　 
  C. 带有宾语从句的复合句的否定形式一般是否定主句。
  Bad: I think he doesn’t like the English teacher. 　　
  Good: I don’t think he likes the English teacher. 
  D.  主句一般过去时态，从句也要用过去时态。
  False: He wanted to know why he is crying in the corner. 　　
  Right: He wanted to know why he was crying in the corner

  宾语从句的否定转移:
  主句的谓语动词是think,believe,imagine,suppose,consider,espect,fancy,guess等。
  并且主句的主语是第一人称而且为一般现在时，从句的否定词一般要转移到主句上来,其反义疑问句一般与宾语从句一致。
  I don’t think he will come to my party.而不能说成I think he won’t come to my party.
  我认为他不会来我的舞会.
  I don’t believe that man is killed by Jim,is he?
  我认为那个人不是Jim所杀的,是不是?
  如果宾语从句中有某个含有否定意义的形容词或副词,其反义疑问句要用肯定形式。
  We find that he never listens to the teacher carefully,does he?
  我们发现他从来不仔细听老师讲课，是不是?

• 宾语从句中引导词的用法比较
  在复合句中作主句的宾语，引导词有：
  连词：that (that 常可省略),whether, if
  代词：who, whose, what ,which
  副词：when ,where, how, why 等。
  
  （一）that引导的宾语从句（在非正式场合that可以省略）
  1.可跟that从句做宾语的动词有：
  say, think, insist, wish, hope, demand, imagine, wonder, know, suppose, see, believe, agree, admit, deny, expect, explain, order, command, feel, dream, suggest, hear, mean, notice, prefer, request, require, propose, declare, report等。
  例句：The boy believes that he will travel through space to other planets.
  注意事项：当主句谓语动词是 think, believe, suppose, expect 等词，而宾语从句的意思是否定时，常把否定转移至主句表示。
  例句：I don’t think it is right for him to treat you like that.
  
  2.在以下情况中that不能省略
  a.当句中的动词后接多于两个由that引导的宾语从句时，第一个that可省，但后面的that不可省。
  例句：He said (that) you were too young to understand the matter and that he was asked not to tell you.
  b.当主句的谓语动词与that宾语从句之间有插入语时，that一般不可省。
  例句：Just then I noticed, for the first time, that our master was wearing his fine green coat and his black silk cap.
  c.当that从句是双宾语中的直接宾语时，that不可省。
  例句：I can’t tell him that his mother died.
  d.注:许多带复合宾语的句子，that引导的宾语从句经常移到句子后部，而用it作形式宾语。
  例句：I find it necessary that we should do the homework on time.
  
  （二）由whether,if 引导的宾语从句
  1.由whether(if)引导的宾语从句，实际上是一般疑问句演变而来的。意思是“是否”。宾语从句要用陈述句语序。
  一般说来，在宾语从句中whether与if可以互换使用，但在特殊情况下if与whether是不能互换的。
  例句：I wonder whether(if) they will come to our party.
  
  2.只能用whether，不能用if引导的宾语从句
  a.在带to的不定式前
  例句：We decided whether to walk there.
  b.在介词的后面
  例句：I’m thinking of whether we should go to see the film.
  c.在动词后面的宾语从句时
  例句：We discussed whether we had a sports meeting next week
  d.直接与or not连用时
  例句：I can’t say whether or not thet can come on time.
  
  3.只能用if不能用whether引导的宾语从句
  a.if引导条件状语从句，意为“如果”
  例句：The students will go on a picnic if it is sunny.
  b.if引导否定概念的宾语从句时
  例句：He asked if I didn’t come to school yesterday.
  c.引导状语从句even if（即使）和as if（好象）时
  例句：He talks as if he has known all about it.

  if,whether在宾语从句中的区别
  a.if和whether在作“是否”解时,引导宾语从句常放在动词know,ask,care,wonder,find out等之后,介词后一般不用if
  b.少数动词,如:leave,put,discuss,doubt后的宾语从句常用whether. 
  c. whether后可以加or not,但是if不可以.
  d.在不定式前只能用whether.
  （如：I can’t decide whether to stay. 我不能决定是否留下。）