从句一、句子的种类英语句子按结构可分三种：1. 简单句: 只包含一个主谓结构的句子，包括五种基本句型1）主语＋谓语；2) 主语＋谓语＋宾语；3) 主语＋系动词＋表语；4) 主语＋谓语＋间接宾语＋直接宾语；5) 主语＋谓语＋宾语＋宾语补语注意：非谓语做状语，也属于简单句，后面句子前不能出现连词。
2. 并列句: 并列句是由两个或两个以上的简单句连接而成。
并列句中的各简单句意义同等重要，相互之间没有从属关系，是平行并列的关系。
它们之间用连词连结。
句型：主谓结构+并列连词(and, but, so, or……) +主谓结构(或更多的主谓结构)注意：并列句连接的两个或两个以上的简单句，短语和句子不能连接。
3. 复合句: 由一个主句和一个或一个以上的从句构成。
句型：引导词+主谓结构+主谓结构；或主谓结构+引导词+主谓结构(从句) (主句) 主句从句定语从句和状语从句。
二、需要注意的问题1.句子原则：一个句子只能有一个主谓结构，谓语是唯一的，谓语由动词构成，如果出现更多动词：①加连词（and / but / so…），变成并列谓语或并列句②加上引导词变成从句③变为非谓语动词2. 英语句子和汉语句子的对比1）英语句子的特点之一是重“形合”，句子的各个部分要由各种连词、关系词等连接起来；而汉语句子是重“意合”，句子前后连接主要是通过上下文的逻辑意义来实现的，连接词的使用远远少于英语，由于这一特点，很多学生在写作时往往忘了使用连接词，造成诸多病句。
2）在汉语中逗号可以直接连接句子，但是在英语中，句子之间连接除了逗号外，还要借助连词。
连词主要有两类，即并列连词和从属连词，并列连词在句中连接并列句，从属连词主要引导从句的。
有一种情况可以不用连词只用逗号连接，那就是独立主格结构。
3）汉语句子中，两个连词可以同时出现在一个句子中，但是在英语中，从属连词和并列连词不能在一个句子中同时使用，只能用一个。
改错：Eg.1) I am tired, I must go to bed.2) He has two sons, both of them are teachers.3) The woman talked to you just now is our English teacher.4) There are many students study in the classroom5) The boy ran to his mother cry.6) After write the notice, he put it up on the wall.7) A person has not enough food, he will not have a healthy body.8) The sun warms the earth, this makes it possible for the plants grow.9) We were looking for your new coat, we could not find it.10)Practise more reading，you will improve your reading ability.11) The person came to see me that afternoon is an old friend of mine.12）He succeeded in passing the exam made his parents very happy.14) It is a pity she didn’t win the prize.15）Tomorrow is Sunday, we don’t need to go to school.16) The work was finished, we went home.17) Time permits, we’ll go out to play.18）Turning to the left, and you will find a bank.19) Hav ing been told many times, but he couldn’t understand it.20) Because he was ill, so he didn’t go to school.21) Though he is a child, but he knows a lot.三、各种从句的引导词的选择关于这个问题是学生学习从句这一内容的最大障碍，要弄清属于什么从句，除t了分清各从句在主句中的位置外，关键在于弄懂各个引导词在从句中的作用。
1.定语从句放在所修饰的名词或代词的后面2.名词性从句分为主语从句，宾语从句，表语从句和同位语从句。
1）主语从句位于主句中的谓语或后置；2）宾语从句位于主句中及物动词或介词和某些形容词之后。
3）表语从句位于主句中的系动词之后；4）同位语从句位于名词如：idea, fact, truth, suggestion, plan之后；3.状语从句位置可以在主句前或主句后；时间、条件、原因,让步状语从句放在句首时需要用逗号及主句隔开。
定语从句一、定语的概念：定语是用来修饰名词或代词的。
比如：a beautiful girl （）three boys （） a shoe factory（）Jim’s father ( ) our teacher ( ) the man in the car （）the man standing at the door （）the man who is talking with Sam （）单个词做定语放在被修饰词_________, 短语或句子做定语放在被修饰词_____________. 二、定语从句的概念及主要特征：1．定语从句：在复合句中，修饰某一_______或__________的从句叫定语从句。
三要素：1）被定语从句修饰的词叫____________；2) 引导定语从句的词叫___________;3) 关系词在从句中充当______________关系词的作用：1）引导___________________; 2)替代___________________; 3) 在从句中充当______________请划出下列句子中的定语从句、先行词及关系代词：The man who is shaking hands with my father is a policeman.2. 关系词的分类及用法关系词分为_________和_______________,定语从句形式功能能否省略关系词先行词限制性定语从句非限制定语从句1、that及which的区别。
1）用that而不用which的情况：①当先行词是不定代词everything, anything, nothing ,something, all, none, few, little, some, much等代词时，或当先行词有every, any, all, some, no, little, few, much等代词修饰时。
②先行词有the only, the very, the last等词修饰③先行词有形容词________或__________修饰；；④先行词既有____又有_____时; ⑤主句的主语是_______或_________⑥若关系代词在从句中作__________，一般需用that。
e.g. All that glitters is not goldThere is nothing that can prevent him from doing it.There is little that I can do for you.This is the very dictionary that I want to buy.This i s the best film that I have ever seen.Mr Smith is the only foreigner that he knows.Who is the man that is standing by the gate?Which is the T-shirt that fits me most?They talked about the persons and things that they remembered at schoolMary is no longer the girl that she was.2）用which而不用that的情况：①引导非限制性定语从句；②代表整个主句的意思；③介词+ 关系代词。
e.g. He had failed in the maths exam, which made his father very angry.This is the room in which my father lived last year.2.that 及who的区别在one, anyone, those 指人时一般用“who”。
he/she/I / they作先行词时, 用“who” 代替“that”.Anyone _____breaks the law is punished.Those _____ break the law are punished.He _____ doesn’t reach the Great Wall is not a true man.2. as引导定语从句时的用法①as引导限制性定语从句，通常用于在主句中常有the same, so或such及as相呼应,（the same …as ; such …as …; so …as）as在定语从句中可作主语、宾语。
e.g. Such machines as are used in our workshop are made in China.Don't do such things as you are not sure about.※比较：Here is so big a stone as no one can lift. （从句）It is so big a stone that no one can lift it. （从句）②as引导非限制性定语从句既可放在主句之前，也可放在主句之后，用来修饰整个句子。
通常用下列句型：as is known to all, as is said, as is reported, as is announced, as we all know,as I expect, as is often the case等。