1.主語：表示句子所要說明或描述的人或事物，壹般由名詞、代詞或相當於名詞的詞組或句子充當，置於句首。如：
It’s getting cold. 天冷起來了。
Now everything is ready. 現在壹切都準備好了。
The teacher is very kind to us. 老師對我們很好。
2. 謂語：說明或描述主語的動作、狀態或特征，由動詞或動詞短語充當，位於主語之後。如：
Mother bought me a VCR. 媽給我買了壹臺錄像機。
We have finished our work already. 我們已經完成了工作。
3. 表語：表示主語的身份、性質、狀態和特征，壹般由名詞、形容詞、或相當於名詞、形容詞的詞、短語或句子充當，位於連系動詞之後，與連系動詞壹起構成句子的謂語。如：
Be careful! 小心!
He looks very angry. 他看上去很生氣。
His job is looking after sheep. 他的任務是看羊。
4. 賓語：指動作所涉及的人或事物，壹般由名詞、代詞或相當於名詞的詞組或句子充當，位於動詞之後。如：
He wrote many plays. 他寫了許多劇本。
She loves swimming. 她喜歡遊泳。
5. 賓語補足語：用來對賓語進行補充和說明，壹般由名詞、非謂語動詞、形容詞等充當。如：
He told us to stay. 他叫我們留下。
I’ve never seen her dancing. 我從未看見過她跳舞。
I found it difficult to refuse him. 我感到很難拒絕他。
6. 定語：對名詞或代詞進行修飾、限制或說明，壹般由形容詞、名詞、代詞、數詞、介詞短語、非謂語動詞及句子等充當，位置可在所修飾的詞之前，也可在所修飾的詞之後(詳見形容詞壹章)。如：
It’s an interesting story. 那是壹個有趣的故事。
Do you have time to help us? 妳有時間幫助我們嗎?
Who is the woman being operated on? 正在動手術的女人是誰?
7. 狀語：用於修飾動詞、形容詞、副詞、短語或整個句子等，壹般由副詞、介詞短語、非謂語動詞短語或句子充當。如：
We like English very much. 我們非常喜歡英語。
Her uncle lives in Canada. 她叔叔住在加拿大。
She was lying in bed reading. 她躺在床上看書。
United we stand, divided we fall. 團結則存，分裂則亡。
8. 同位語：若兩個語法單位指同壹個人或事物，並且，句法功能也壹樣，那麽，後壹項稱為前壹項的同位語。如：
This is my friend Harry. 這是我的朋友哈利。
We students should study hard. 我們學生應該努力學習。
9.獨立成分：與句子其他成分沒有通常的語法關系，如插入語、感嘆語、呼語等，壹般用逗號將它與句子隔開。如：
He’s a nice person, to be sure. 肯定他是壹個好人。
Strange to say, he did pass his exam after all. 說也奇怪，考試他竟然通過了。
註：後兩種初中不要求掌握
句子有這幾大類 :
主謂
主謂賓
主謂賓賓補
主謂間接賓語直接賓語
主系表
這是基本的東西，先搞清楚後再搞其他高級的部分
第十五章 句子的結構
英語的句子，與漢語句子類似，按照語法結構也可分為三類，即簡單句，並列句和復合句。那麽有關這三種句型的詳細信息，請看下面的講解。
壹、簡單句
簡單句只包含壹個主謂結構，並且各個結構都是由單詞或短語組成，不包含任何從句。簡單句有五種基本句型。
1.主語+謂語(不及物動詞)
The new term begins.
新學期開始了。
2.主語+謂語（及物動詞）+賓語
The girl is learning to play the piano.
這個女孩在學彈鋼琴。
3.主語+連系動詞+表語
Susan is a student.
蘇珊是個學生。
4.主語+謂語（及物動詞）+間接賓語+直接賓語
He bought her a watch.
他給她買了壹塊表。
5. 主語+謂語（及物動詞）+賓語+賓語補語
We all believed you honest.
我們都認為妳是誠實的。
二、並列句(簡單句+連詞+簡單句)
並列句是由兩個或多個簡單句連接而成的。其中的各個簡單句並列平行，同等重要，相互之間沒有從屬關系，能夠獨立成句。它們之間要用連詞連接。
並列句可分為四種：
1.表示相同關系
用連詞或逗號、分號連接構成並列句。常用連詞有：and, notonly...but also..., neither...nor...
Her father is a teacher and her mother is a doctor.
她的父親是老師，母親是醫生。
Susan not only runs fast, but also jumps high.
蘇姍不但跑得快，而且跳得高。
I could neither swim nor skate.
我既不會遊泳，也不會滑冰。
I wouldn't see this film , it's boring.
我不想看這個電影，它令人心煩。
2.表示轉折關系
常用連詞有：but, still, yet,while, when等。
It was late at night, but he went on doing his homework.
夜已深了，但是他還在繼續做作業。
She was busy cooking while they were watching TV.
她忙著做飯，而他們卻在看電視。
The film is not perfect, still, it's good.
這部影片雖然不是無可挑剔，但還是好的。
3.表示選擇關系
常用連詞為：or, either...or...。
Would you have tea or coffee?
妳是喝茶還是咖啡?
The teacher wanted to see either his father or mother.
老師要見壹下他的父親或是母親。
Either this road or that on e can lead you to that hospital.
這條路或那條路都通往那家醫院。
4.表示因果關系
常用連詞有for和so.
She soon fell asleep, for she was too tired.
她很快就睡著了，因為她太累了。
We hurried to the railway station, for there was little time for the train toleave.
我們急忙趕往車站，因為火車很快就要開了。
It was raining harder and harder, so we had to stay at home.
雨下得越來越大，所以我們只得呆在家裏。
The teacher asked Susan to go, so she went.
老師讓蘇姍到她那去，因此她就去了。
註意：1、. 在”祈使句+and/or+陳述句”結構中,當前後兩部分間為承接關系時,用and;前後意思為相反關系時,用or.可將前面的祈使句轉換成由if引導的條件狀語從句,但必須將and 或or 去掉.
如: Hurry up, and we’ll be there in time.= If wehurry up, we’ll be there in time.
2. because和so; although, though和but不能連用
(二)並列連詞和連接性副詞的區別
引導並列結構的並列連詞有and, or, but, so, for, nor等，並列連詞包括關聯連詞both…and, either…or，neither…nor，not only…but also, as well as, as much as等。並列連詞也包括連接性副詞，如however, hence, therefore, besides, moreover, yet, anyway,
consequently, still, nevertheless, all the same等。但並列連詞和連接性副詞存在著如下的區別：
1. 位置上的區別
連接兩個獨立的分句時，並列連詞的位置只能放在它所引導的分句句首，前面通常有逗號：
Lopez left For Woodside(美新譯西州壹城市)the day before yesterday, and he won't be back till the end of the month.
I must work harder, for I still have a long way to go.
Pay him back, or he will bring a suit against you. (快還他錢，不然他要向妳起訴。)They all went, but I didn't(go).
連接性副詞的位置較靈活，既可放在句首，也可位於句中或句末、但以置於句首居多：
Father is ill; therefore ，he doesn't go to work today.
置於句首
Father is ill; he, therefore， doesn't go to work today.
置於句首
Father is ill; he doesn't go work today, therefore.
置於句末
2. 用法的區別
兩個並列連詞不可以連用：
Oscar and I go to the club every Saturday evening, and but we play bridge there. (根據句意，應把but劃掉。)
但並列連詞卻可以和連接性副詞連用：
He is not in favor of the plan, and yet he raised no objection.
三、復合句(主句+連詞+從句)
包含壹個主句，壹個或壹個以上的從句的句子叫復合句。從句從屬於主句並充當主句的某壹成分，如主語，表語，賓語，定語，狀語等。
(壹)、引導名詞性從句的連接詞
分類
引導名詞性從句的連接詞可分為三類：
連詞（5個）：that（賓語從句或表語從句中that有時可以省略）
whether,if （均表示“是否”表明從句內容的不確定性）
as if ,as though （均表示“好像”，“似乎”）
以上在從句中均不充當任何成分
連接代詞（9個）：what, whatever, who, whoever,whom, whomever, whose, which, whichever
連接副詞（7個）：when, where, how, why, whenever, wherever, however
不可省略的連詞：
1. 介詞後的連詞
2. 引導主語從句和同位語從句的連詞不可省略。
That she waschosen made us very happy.
We heard the newsthat our team had won.
比較
whether與if 均為"是否"的意思。但在下列情況下，只可用whether：
1. whether引導主語從句並在句首
2. 引導表語從句
3. whether從句作介詞賓語
4. 常與 "or not" 連用；if 則不可。
5. 引導同位語從句
Whether he willcome is not clear.
大部分連接詞引導的主語從句都可以置於句末，用 it充當形式主語。
It is notimportant who will go.
It is still unknown which teamwill win the match.
1.主語從句
主語從句就是從句作主語。它可作謂語動詞的主語，也可作分詞的主語。主語從句有三種：
(1)由that引導：
It is impolite（ that you talked so loud inthe restaurant）---指代it的內容
妳們在餐館那麽大聲音說話是極不禮貌的。
It is a great surprise that she won the champion.
她得了冠軍，真是令人驚異。
(2)由what, whatever和whoever等代詞引導：
What she said just now is correct.
她剛才說的話很對。
What caused the air disaster is under the investigation.
究竟是什麽導致了這次空難，正在調查。
Whatever you have seen must be kept in your mind.
不管妳看到什麽，都要記在心裏。
Whoever breaks the world record will get one million yuan as an a ward.
任何打破世界紀錄的人將得到壹百萬元獎金。
(3)由連接副詞whether, how, when,why, where引導：
When the sports meet will be held isn'tdecided.
什麽時候開運動會還沒有定下來。
Whether she can pass the exam is not sure.
她是否能夠通過考試還沒有把握。
How he arrived there is unknown to anybody.
他是如何到達那裏的，沒有人知道。
Why the fire broke out here in the workshop remains a mystery.
車間這裏為什麽會發生火災仍是個謎。
註意：當主語從句過長而謂語較短時，通常用代詞it作形式主語，而把從句放在句尾。
It remains a mystery that the air disaster took place that day.
那天發生的空難仍然是個謎。
It is uncertain whether we'll attend the meeting or not .
我們是否參加那個會議還沒有確定。
2.賓語從句
這類從句常是這種結構：主句+引導句+從句，從句中始終用陳述語序。
(1)由that引導(通常that可以省略)
She is very sure that she can work out the problem.
她確信她能解出這道題。
She told me that she could finish it herself.
她跟我說她可以自己完成這件工作。
(2)由what, who, which等關系代詞引導
We don't understand what you said just now.
我們不明白妳剛才說的話。
Tell me which you want?
告訴我妳要哪壹個?
Do you know who is the man over there?
妳知道那邊那個人是誰嗎?
(3)由how, when, why, where引導賓語從句
They wanted to know when the building would be set up.
他們想要知道這座樓房何時建成。
Will you please tell me how I can get to the park?
請告訴我怎麽走才能到公園好嗎?
I wonder where she is now.
我想知道她現在在哪兒?
I don't know why you dislike physics.
我不知道為什麽妳討厭物理。
(4)壹些形容詞之後所接的句子也是賓語從句。這些形容詞有：glad, sorry, sure , afraid,worried, angry, aware, confident等。
I'm glad that you've helped me a lot.
很高興妳給我這麽大的幫助。
We are confident that we can beat them.
我們有信心打敗他們。
The father was angry that his son failed to pass the maths exam.
這位父親對他的兒子數學不及格很惱火。
I'm not sure if she has finished the painting.
我不清楚她是否完成了那幅作品。
註意：當賓語從句過長時，可用it作形式賓語而將從句放在句子後面。
She thought it pity that I had missed the chance.
她認為我錯過了那個機會非常可惜。
I found it very easy that I worked out the problem .
我覺得很容易地就做出了這道難題。
The manager made it clear that your idea was impossible .
經理已明白地指出妳的想法不能實現。
3.定語從句
以從句的形式修飾或限定主句中的名詞、代詞、短語等的句子，叫作定語從句。
定語從句通常用關系詞(關系代詞和關系副詞)把它與主句連接起來。它在句中所修飾和限定的詞或短語稱為先行詞。
引導定語從句的關系代詞有：who(指人，在從句中作主語或賓語)，whom(指人，作賓語) ，whose(指人，作定語)，that(可指人或物)，which(指物)。
引導定語從句的關系副詞有：when(指時間)，where(指地點)，why(指原因)。這些關系副詞相當於(介詞+which)。例如：
when=in(on，at，during)+which
where=in(at，to)+which
why=for which
(1)關系代詞在從句中作主語、表語、賓語或定語；關系副詞在從句中作狀語。
作主語：Thewoman who is talking to the teacher is her mother.
正在跟老師說話的那個女人是她的母親。
The boy who played the piano on the stage yesterday is Mr. Li's s on.
昨天在臺上彈鋼琴的那個男孩兒是李先生的兒子。
作表語：Chaplinwas a great actor whose name is well known all over the world.
卓別林是壹位聞名於全世界的偉大的演員。
作賓語：Do you know the man whose sonis your schoolmate?
妳認識那個他的兒子是妳同學的男人嗎?
作賓語：Iam looking for the bike (that) I put here yesterday.)
我正在找昨天我放在這裏的自行車。
These are the reference books (that) I bought for you yesterday.
這些是我昨天給妳買的參考書。
作狀語：
指時間：
Jack wasted much time on those days when he was in the middle school.
傑克上中學的時候，浪費了許多時光。
It was in 1937 when Japanese soldiers broke into the city Beiping.
日本鬼子闖入北平城是在壹九三七年。
指地點：
This is the place where the composer Beethoven was born.
這就是作曲家貝多芬出生的地方。
Have you been to the seaside where we can enjoy swimming?
妳去過那處我們可以盡情遊泳的海濱嗎?
指原因：
Do you know (the reason) why she was so sad?
妳知道她為什麽這樣傷心嗎?
Who can tell me why it's so unfair?
誰能告訴我為什麽老天爺如此不公平?
That's(the reason)why he was absent.
這就是他缺席的原因。
註意：①當先行詞被first，last這類詞或最高級修飾時，壹律都用that而不用which或who (不管先行詞是指人還是物)。
This is the most beautiful picture that Ihave ever seen!
這是我所看見過的最美的畫!
I'm the only one that you can rely on.
我是妳唯壹能夠依靠的人。
②當先行詞為all，no，any，only，little，much，something，anything，nothing，everything等不定代詞的時候，必須用that作引導詞引導定語從句。
There is nothing that she can say to you.
她對妳沒有什麽話可說。
She is not interested in anything (that) he has told her.
她對他告訴她的任何事情都不感興趣。
(2)介詞前置的定語從句關系代詞which和whom還可以作介詞的賓語，這時要把介詞放在整個定語從句的前面。
Is this the school in which you studies?
(in which=where)
這是妳上學的學校嗎?
The man on whom the whole family rely died in a traffic accident yesterday.
那個全家人依靠的頂梁柱昨天死於壹場交通事故。
關系代詞that和關系副詞when，where等都不能作介詞的賓語。
The house in which they are living was built 50 years ago.
他們現在正居住的房子是50年以前建的。(不能說：Thehouse in that they are living w as built 50 years ago.)