句子成分和句子种类详解句子成分和结构是英语的基础，是理解和表达英语的关键。
英语中许多词类都对句子成分和结构有影响。
英语中的句子是由词或短语组成的，这些词或短语在句子中起一定的作用，叫做句子成分。
英语的篇章是由句子构成的，不同的内容需要不同类型的句式结构，这些句式结构又构成英语中不同的句子类型。
学习英语句法的基础是了解句子成分、句子的基本结构和句子种类。
I 句子成分组成句子的各个部分叫做句子成分。
句子成分包括主语、谓语、表语、宾语、同位语、定语、状语和补足语等。
主语和谓语是句子的主体部分；表语、宾语、定语、状语、补足语和同位语等是句子的次要部分。
1.主语：主语说明谓语动作或状态的执行者，常用的作主语的词类有：名词（短语）、代词、数词、不定式（短语）、动名词（短语）和从句。
Subject is the topic or theme of the sentence, which tells of what the sentence is about.1）名词：The students are learning grammar.Our teacher speaks very fast.2）代词：She is writing.He likes playing tennis.3）数词：Five is an odd number.Six is my favourite number.4）不定式：To learn English well is important.It is not easy to remember all rules.5）动名词：Swimming is interesting.Learning grammar well is difficult.6）主语从句：What I said is true.What we can't get seems better than what we have.2.谓语：谓语用来描述主语的行为动作或所处的状态。
谓语的中心词是限定动词，有人称、数和时态的变化。
Predicate says something about the subject and bears the new information which the speaker or writer wants to transmit to the listener or reader.1）简单谓语动词：He bought a dictionary yesterday.动词短语：He is looking for his pen.2）复合谓语系动词+表语：We are students.情态动词+不定式：I may be wrong.动词+不定式：We have to do something for them.3.表语：表语与前面的系动词一起构成复合谓语，用来说明主语的特征、类属、状态、身份等。
充作表语的可以是单词、短语或从句。
Predicative expresses the status, characteristics or the quality of the subject.1）名词：He is a doctor.Mr. Scott is a farmer.2）代词：It is me.That's something we have always to keep in mind.3）数词：My lucky number is nine.She was the first to learn about it.4）形容词：The classroom is big.His hair has gone white.5）副词：I am here.6）介词：We are in the classroom.7）动名词：My job is teaching them grammar.= Teaching them grammar is my job.8）分词：The film is exciting.Time is pressing. Let's hurry up.9）不定式短语：My job is to teach them grammar.All I can do is to send her a telegram.10）表语从句：He looks as if he were going to cry.The suggestion is that we should recite more words.注意：名词：身份、性质、内容。
形容词：特点、特征。
4.宾语：宾语为动作的承受者。
Object represents the person or the thing that something is done to or the person who is concerned in the result of an action.1）名词：He is drinking water.I've bought an English-Chinese dictionary.2）代词：The teacher is talking to her.They didn't promise him anything.3）数词：I like six.I want the first.4）动名词：He likes watching TV.I enjoyed working with you.5）不定式：I want to buy a book.My father likes to swim in winter.6）宾语从句：He asked if he might go there.Did you write down what she said?注意：英语有单宾语、双宾语、复合宾语、同源宾语等。
1）单宾语：I can hardly hear the radio. Would you please turn it up?Please stop making noise.Do you understand what I mean?2）双宾语：双宾语指动词后面接指人和指物的两个宾语。
（指人的宾语叫间接宾语；指物的宾语叫直接宾语）其结构为：主语+及物动词（短语）+sb. + sth.Please tell me how the accident came about.（me为间接宾语，how从句为直接宾语）The teacher asked me a question.（me为间接宾语，a question为直接宾语）当直接宾语与间接宾语位置调换时，须在间接宾语前加介词to/ for等。
Would you like to do me a favor?= Would you like to do a favor for me?3）复合宾语：“宾语+宾语补足语”构成了复合宾语，宾语与补足语之间具有逻辑上的主谓关系。
We all find him a nice boy.（him为宾语，a nice boy为宾语补足语）I saw a stranger waving to me.（a stranger为宾语，waving to me为宾语补足语）4）同源宾语：同源宾语指由名词担任的能重复动词部分或全部意思的直接宾语，前面常有修饰语。
laugh a good laugh大笑smile a gentle smile 微微一笑live a happy life 过着幸福生活die a glorious death 死得光荣dream a beautiful dream 作美梦sing a sweet song 唱了一首甜美的歌blow a heavy blow 沉重地一击5.同位语：对句子中某一成分作进一步解释、说明，与前面的词在语法上处于同等地位的句子成分叫做同位语。
同位语常常置于被说明的词之后。
Appositive is the further information after a noun or a pronoun referring to "who" or "what".1）名词：Zhang Sir, our grammar teacher is humorous.This is Mr. Zhou, director of our hospital.2）代词：He himself did it.3）数词：The year, 1988 is important.We two will go shopping this afternoon.4）动名词：My task, looking after these children is important.5）不定式：My job, to teach them grammar is hard.6）同位语从句：I had no idea that you were here.The suggestion that we should recite more words is useful.6.定语：定语是用来描述名词或代词的修饰语，它常和名词构成名词短语。
Attributive is used to modify a noun or a pronoun.前置定语：1）名词：I want an English-Chinese dictionary.He has bought a grammar book.2）代词：This is my bag.No difficulty whatever can stop our advance.3）数词：There are two policeman in the street.Please read the first paragraph.4）冠词：This is a desk.5）形容词：I like red apples.He gave me a vivid description of the battle.6）动名词：This is a sleeping car.The swimming pool is wonderful.后置定语：7）副词：The students here are good.The buildings around are of modern construction.8）介词：The students in the classroom are good.The book on the desk is mine.9）不定式：I have an apple to eat.I have a lot of homework to do.注意：当句子的主语是不定式动作的发出者时，不定式用主动形式表被动。