1、Unit 4我們知道在句子中起名詞作用的句子叫我們知道在句子中起名詞作用的句子叫名詞性從句。名詞性從句的功能相當于名詞性從句。名詞性從句的功能相當于名詞詞組，它在復合句中能擔任主語名詞詞組，它在復合句中能擔任主語, 賓語，表語，同位語，介詞賓語等，因賓語，表語，同位語，介詞賓語等，因此根據它在句中不同的語法功能，名詞此根據它在句中不同的語法功能，名詞從句又可分別稱為主語從句，賓語從句，從句又可分別稱為主語從句，賓語從句，表語從句和同位語從句。表語從句和同位語從句。Read the two sentences firstly.What it was to become was uncertain

2、 until between 4.5 and 3.8 billion years agoit was not clear whether the shape would last or not.通過觀察，我們發(fā)現(xiàn)兩句當中劃線部分通過觀察，我們發(fā)現(xiàn)兩句當中劃線部分的句子都在復合句中起名詞的作用，因的句子都在復合句中起名詞的作用，因此稱之為主語從句。此稱之為主語從句。主語從句在復合句中作句子的主語。引主語從句在復合句中作句子的主語。引導主語從句的詞有導主語從句的詞有從屬連詞從屬連詞that, whether, if；連接代詞連接代詞who, whoever, whom, what, whateve

3、r, whose, which；連接副詞連接副詞when, where, how, why等。等。觀察下列例句，指出其中所包含的主語觀察下列例句，指出其中所包含的主語從句及引導詞從句及引導詞:1. What is needed for a long trip is careful preparation.該句中主語從句是該句中主語從句是 _，引導詞為，引導詞為 _。What is needed for a whatlong trip2. That Jay Zhou will come to my city excites everybody.該句中主語從句是該句中主語從句是 _ _，引導詞為，

4、引導詞為_。3. Whether we will travel abroad or not has not been decided.該句中主語從句是該句中主語從句是 _ _，引導詞為，引導詞為_。That Jay Zhou willWhether we willcome to my city thattravel abroad or notwhether4. Whoever knows the secret mustnt tell others.該句中主語從句是該句中主語從句是_ _，引導詞為，引導詞為_。5. It remains a puzzle why dinosaurs died o

5、ut suddenly long time ago.該句中主語從句是該句中主語從句是_，引導詞為，引導詞為_。Whoever knows the whoeverwhy dinosaurs diedwhysecretout suddenly long time ago【觀察總結【觀察總結】 通過分析上面例句，同學們可能會發(fā)通過分析上面例句，同學們可能會發(fā)現(xiàn)上面第現(xiàn)上面第5句中的主語從句似乎比較隱蔽。句中的主語從句似乎比較隱蔽。其實，這也是主語從句的一種呈現(xiàn)方式，其實，這也是主語從句的一種呈現(xiàn)方式，即：即：當一個句子主語過長時，可以用當一個句子主語過長時，可以用it作作形式主語，而把真正的主語或主

6、語從句后形式主語，而把真正的主語或主語從句后移至句子末尾，以保持句子的平衡。移至句子末尾，以保持句子的平衡。注意注意觀察下列例句中的劃線部分：觀察下列例句中的劃線部分：It is not clear how the accident happened.It is not hard to understand why he did so at that time.It is a pity that you should have made such a careless mistake.It is reported that more than thirty deaths were caused

7、 in the accident.不難看出，雖然上面例句中都用不難看出，雖然上面例句中都用it作形式作形式主語，但句子結構卻不盡相同。現(xiàn)將常主語，但句子結構卻不盡相同?，F(xiàn)將常見的見的由由it作形式主語的句型總結如下作形式主語的句型總結如下：1. It be + n. + that從句從句2. It be + adj. + that從句從句，常見此類形容，常見此類形容詞有：詞有：important, necessary, clear, certain, natural, strange, obvious, likely, impossible, possible等。等。3. It+不及物動詞不及

8、物動詞+that從句從句It seems / appears . that . 似乎似乎It happened (to sb.) that . （某人）碰巧（某人）碰巧4. It + be + 過去分詞過去分詞 + 主語從句主語從句It is said / reported / believed / suggested / known / proved that .【要點精講【要點精講】1. what與與that引導主語從句引導主語從句觀察下列例句，試著翻譯例句并總結觀察下列例句，試著翻譯例句并總結其規(guī)律。其規(guī)律。(1) What you lack is self-confidence. 譯為

9、：譯為：_你所缺乏的是自信。你所缺乏的是自信。(2) That more and more students are admitted into universities is true.譯為：譯為：_ _(3) What is needed for the program is more wisdom. 譯為：譯為：_這個項目所需要的是更多的智慧。這個項目所需要的是更多的智慧。越來越多的學生將被大學錄取越來越多的學生將被大學錄取的消息是真實的。的消息是真實的。從上面例句可以看出，從上面例句可以看出，that引導主語從引導主語從句時，在句中具有句時，在句中具有“兩不兩不”原則：原則：一、不作句

10、子成分；一、不作句子成分；二、沒有實際意義。二、沒有實際意義。當它當它引導的主語從句置于句首時，引導的主語從句置于句首時，that不能省略不能省略；如果；如果用用it作形式主語，而把作形式主語，而把主語從句放在句末時，主語從句放在句末時，that通常也不可通常也不可以省略以省略。而而what引導的從句則恰恰相反，引導的從句則恰恰相反，what在從句中的作用為：在從句中的作用為：一、作句子成分；一、作句子成分；二、除了起到引導從句的作用外還二、除了起到引導從句的作用外還 要承擔具體的意義。要承擔具體的意義?！眷柟叹毩暋眷柟叹毩暋?用用what或或that填空。填空。(1) _ he told u

11、s this morning was just a lie.(2) _ is important to us is enough time.(3) It worries my mom _ she is beginning to get a little fat.(4) _ we cant get seems better than _ we have.WhatWhatthatWhatwhat2. whether與與if引導主語從句引導主語從句 如果如果主語從句置于句首，不能用主語從句置于句首，不能用if引導，此時，需用引導，此時，需用whether。但如果用。但如果用it作形式主語，而把主語從

12、句放在句末作形式主語，而把主語從句放在句末時，也可以用時，也可以用if引導。引導?！眷柟叹毩暋眷柟叹毩暋?用用whether或或if填空。填空。(1) It doesnt matter _ he will come or not.(2) _ well go camping tomorrow depends on the weather.(3) It was doubtful _ Tom really saw Sharon.(4) _ Tom really saw Sharon was doubtful.whether / ifWhetherwhether / ifWhether3. 其它引導詞

13、其它引導詞 連接代詞連接代詞who, which, whom, whose有各自的具體意義，起連接作用，同時有各自的具體意義，起連接作用，同時在從句中充當主語、賓語、表語、定語在從句中充當主語、賓語、表語、定語等；等；whoever, whatever, whichever在意在意義上更為強調，常譯為義上更為強調，常譯為“無論無論”；連；連接副詞接副詞when, where, why, how等也有各等也有各自的意義，起連接作用，并在從句中作自的意義，起連接作用，并在從句中作狀語。狀語?！境Ｒ婂e誤展示【常見錯誤展示】 下列各句均有一處錯誤，請改正并下列各句均有一處錯誤，請改正并分析錯誤的原因。

14、分析錯誤的原因。1. Light travels faster than sound is common knowledge.Thatthat雖無詞義但引導主語從句位雖無詞義但引導主語從句位于句首時不能省略。于句首時不能省略。if, whether都可表示都可表示“是否是否”, 但但if不能引導句首主語從句。不能引導句首主語從句。2. If shes coming or not doesnt matter much.Whether shes coming or not doesnt3. That the professor said is of great importance.4. Wher

15、e will the trees be planted has not been decided.Whatthat引導主語從句時無詞義。引導主語從句時無詞義。What the professor said表示表示“教授所說的教授所說的”。將將will置于置于trees之后。主語從句要之后。主語從句要用陳述句語序。用陳述句語序。5. No matter who breaks the rule will be punished.6. When and where the meeting will be held still remain a question.引導讓步狀語從句時二者可互換，但引導讓

16、步狀語從句時二者可互換，但引導名詞性從句時只能用引導名詞性從句時只能用whoever。Whoever 主語從句表示單一概念時，謂語要用主語從句表示單一概念時，謂語要用單數形式。單數形式。remains7. What were your problems a year ago has now become mine.has要改為要改為have。主語從句表示復數。主語從句表示復數概念時，謂語要用復數形式。概念時，謂語要用復數形式。haveRewrite the following sentences with noun clauses as the subject. 1. His discover

17、y has not yet been proved. 2. Do the other astronomers accept his ideas? It remains a question.What has not yet been proved is his discovery. Whether the other astronomers accept his ideas remains a question.3. The first appearance of life on earth is still a mystery to scientists. 4. Why is the ear

18、th becoming warmer? It is an important topic for research.How life first appeared on earth is still a mystery to scientists.Why the earth is becoming warmer is an important topic for research.5. Stephen Hawking at 65 experienced zero gravity during a flight. It amazed everybody.6. Pluto is no longer

19、 considered a planet in our solar system. What a surprise!It amazed everybody that Stephen Hawking at 65 experienced zero gravity during a flight.It is a surprise that Pluto is no longer considered a planet in our solar system.用適當的連接詞補全下面的對話用適當的連接詞補全下面的對話。Lucy: Why are you looking so happy?Jenny: Iv

20、e just attended a lecture. _ the speaker said made me excited.Lucy: What was it about?Jenny: About health. It seems _ a lot of people dont know how to keep healthy.What that Lucy: Sounds great. _ Im concerned about is my health condition at the moment. But what should I do to be healthy?Jenny: _ you

21、 will stay healthy depends on two factors exercise and diet.Lucy: You know I always do some running on the road every night.What WhetherJenny: Whether you take exercise is one thing, but _ you take exercise is quite another. You shouldnt run at night because it will affect your sleep. Besides, _ you do your running