题文

Tom knew nothing about it              his sister told him.

[     ]

A. since B. if C. until D. unless

题型：单选题  难度：中档

答案

C

据专家权威分析，试题“Tom knew nothing about it his sister told him. [ ]A. since..”主要考查你对  从属连词，状语从句  等考点的理解。关于这些考点的“档案”如下：

从属连词状语从句

考点名称：从属连词

• 从属连词：
  这种连词是用以引导名词性从句定语从句和状语从句的，由从属连词所引导的句子叫从句,而含有从句的句子叫作复合句。

• 从属连词可分为三大类：
  1、that （无词义，不做成分）
  if，whether （表达是否的意义，但不做句子成分）
  2、连接代词：who，whom，whose，what，which，whatever, whoever, whichever（有词义，在句子中可作主语、表语、宾语）
  3、连接副词：when，where，why，how，how many，how long，how far，however，whenever，wherever （有词义，作从句的状语）

  用法：
  从结构上说，英语连接词分两大类：并列连词和从属连词。
  
  并列连词连接两个或两个以上地位平等的字、词组或分句。例如：
  (1) Air and water are indispensable to me. 　　
  (2) She likes going out with friends or playing outdoor games. 　　
  (3) Most workers have a good income, so they look very happy. 　　
  
  从属连词连接两个或两个以上的分句，形成复杂句中的从属分句。例如： 　　
  (4) He said that he did not want to go . 　　
  (5) Many things have happened since I last saw him. 　　
  (6) You may come if you want to. 　　
  
  从属连词用来连接各种从句。
  until(till)直到，在用until表达时间状语的句子中，主句中的动词是要十分小心去选择的。
  如动词是持续行动词，它要用肯定句，如：
  I studied hard until 12 o'clock last night.
  如果动词是瞬间截止性动词，则要用否定句，如:
  He didn't go to bed until his mother came back.
  由since,for,by,before, 来引导的时间状语从句。
  since 引导的时间状语是动作的开始时间，如:
  I have studied English since 1990.
  而by引导的时间状语通常是动作的结束时间，如：
  I had learned 25 English songs by the end of last term.

• 从属连词语法分类：
  

  种类	语法作用	连词举例
  从属连词	引导原因状语从句	Because, since
  	引导条件状语从句	If, unless, as long as
  	引导目的状语从句	So that
  	引导结果状语从句	So…that
  	引导方式状语从句	As, just as, as if
  	引导让步状语从句	Though, although, even though, no matter what, however, no matter how, whoever, no matter who, wherever, no matter where
  	引导比较状语从句	As…as, not so…as, than, less…than, the more…the more
  	引导名词性从句	Who, whom, whose, which, that, when, where, why

考点名称：状语从句

• 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。

• 状语从句分类:
  1、时间状语从句
  常用引导词：
  when, as, while, as soon as, while, before, after, since , till, until
  特殊引导词：
  the minute, the moment, the second, every time, the day,the instant, immediately , directly, no sooner … than, hardly …when, scarcely … when
  I didn't realize how special my mother was until I became an adult.
  While John was watching TV, his wife was cooking.
  The children ran away from the orchard(果园) the moment they saw the guard.
  No sooner had I arrived home than it began to rain.
  Every time I listen to your advice, I get into trouble.
  
  2、地点状语从句
  常用引导词：
  where
  特殊引导词：
  wherever, anywhere, everywhere
  Generally, air will be heavily polluted where there are factories.
  Wherever you go, you should work hard.
  
  3、原因状语从句
  常用引导词：
  because, since, as, for
  特殊引导词：
  seeing that, now that, in that, considering that, given that, considering that, as much as, so much as
  My friends dislike me because I'm handsome and successful.
  Now that everybody has come, let's begin our conference.
  The higher income tax is harmful in that it may discourage people from trying to earn more.
  Considering that he is no more than 12 years old, his height of 1.80 m is quite remarkable.
  
  4、目的状语从句
  常用引导词：
  so that, in order that
  特殊引导词：
  lest, in case, for fear that,in the hope that, for the purpose that, to the end that
  The boss asked the secretary to hurry up with the letters so that he could sign them.
  The teacher raised his voice on purpose that the students in the back could hear more clearly.
  
  5、结果状语从句
  常用引导词：
  so that, so… that, such … that,
  特殊引导词：
  such that, to the degree that, to the extent that, to such a degree that,
  He got up so early that he caught the first bus.
  It's such a good chance that we must not miss it.
  To such an degree was he excited that he couldn't sleep last night.
  
  6、条件状语从句
  常用引导词：
  if, unless,
  特殊引导词：
  as/so long as, only if, providing/provided that, suppose that, in case that, on condition that
  We'll start our project if the president agrees.
  You will certainly succeed so long as you keep on trying.
  Provided that there is no opposition, we shall hold the meeting here.
  
  7、让步状语从句
  常用引导词：
  though, although, even if, even though
  特殊引导词：
  as(用在让步状语从句中必须要倒装),while ( 一般用在句首 ),no matter …, in spite of the fact that, while, whatever, whoever, wherever, whenever, however, whichever
  Much as I respect him, I can't agree to his proposal.
  尽管我很尊敬他, 我却不同意他的建议。
  The old man always enjoys swimming even though the weather is rough.
  No matter how hard he tried, she could not change her mind.