人教版高中英語選修六Unit3Ahealthylife知識講解it的用法(1)

1、it的用法（1）編稿：牛新閣審稿：王春霞概念引入小詞it是我們學(xué)英語之初就學(xué)會的，是不是感覺它似乎有點無所不能，經(jīng)常出現(xiàn)呀？ 那么我們是不是已經(jīng)了解了it的用法了呢？本單元和下單元我們就把it的用法做一小結(jié)。先看這些句子，想想it的用法是什么？1. It is a beautiful day here and I am sitting under the big tree at the end of the garden.（表天氣）2. It seems amazing that at my age I am still fit enough to cycle 20 kilometres in

2、 an afternoon.（代替that從句作主語）3. Its my birthday in two weeks time and I ll be 82 years old!（表時間）4. Your mother tells me that you started smoking some time ago and now you are finding it difficult to give it up.（第一個it代替to give it up作賓語；第二個it代替上文中“吸煙”的事） 下面我們就先學(xué)習(xí)it作為代詞和形式主語、形式賓語的用法。用法講解代詞it1 .作人稱代詞人稱代詞i

3、t是有實義的，是單數(shù)第三人稱代詞。主格與賓格相同。1）指代人以外的一切生物或事物，如前文提到的事物或未指明但談話雙方都知道的那件事；Ningbo is a beautiful city, isn t it?寧波是座美麗的城市，是不是？It doesn;t matter.沒關(guān)系。2）替代前文中的this, that;This is your plan? Will you hand it in? 這是你的計劃？你要交上去嗎？3）指代嬰兒、小孩或性別不明的人。The baby is crying. It might be hungry. 嬰兒在哭，或許餓了。 Someone is ringing.

4、Who might it be? 有人按門鈴，可能是誰呢？-It must be my friend Tom . He （不可用 It） wants to see you .一定是我的朋友湯姆，他想要見你。2 .作非人稱代詞it用作無人稱的主語，不指物，而表示時間、天氣、氣候、季節(jié)、距離等自然現(xiàn)象，或 指事物的狀態(tài)。What a long way it is from Beijing to London! （it 指距離）從北京到倫敦是多么長的一段距離啊！It was nearly midnight when she came back. （it 指時間）她回來時快半夜了。It was ver

5、y quiet in the caf . （it 指咖啡館里靜悄悄的。Its early spring, but its already very hot.（前面的 it 指季節(jié)，后面的 it 指氣溫）剛是初春，但是已經(jīng)很熱了。If it hadnt been for the snow, we could have climbed over the mountain.（it 指情況）要不是因為下雪，我們可能已經(jīng)翻越了那座山。易誤辨析區(qū)另1J it, one, it, that 和 which1. it指上文出現(xiàn)過的同一事物，而one則泛指與前面事物同屬一類中的一個。This was the l

6、ast dictionary in that bookstore. So I took it. （it 特指前面提到的那本詞典）這是那家書店最后一本詞典，所以我買下了它。There are many dictionaries in that bookstore. So I bought one. （one 泛指其中之一）那家書店有許多詞典，所以我買了一本。2. that做代詞替代前面提到的事物，可數(shù)名詞、不可數(shù)名詞皆可。代替可數(shù)名詞可以用the one替換。that的復(fù)數(shù)形式為those只可替代可數(shù)名詞復(fù)數(shù)，在句中相當于the ones。The head teacher in your cla

7、ss is younger and more active than that in theirs.你們班的班主任比他們班的班主任年輕而且更活躍。The students who do best in the exam are not always those with the best brains.考試考得最好的學(xué)生并不總是那些最聰明的學(xué)生。3. that在并列分句中，可以替代前面某一個名詞或整個句子內(nèi)容，可用it替換.She heard a terrible noise, and that brought her heart into her mouth.她聽見一個可怕的聲音，讓她的心跳

8、到了嗓子眼。4. it和which都可以用來指某一件事，關(guān)鍵要看中間是否有并列連詞，如果有就用it,反之用which。The Smiths bought a new house, but it will need a lot of work before they can move in.史密斯家買了一座新房子，但是搬進去之前還需要大量的工作。（it指代前面提到的那所房子，此句的關(guān)鍵詞是but,連接兩個分句，it是分句的主語）The Smiths bought a new house, which will need a lot of work before they can move in.

9、（因為沒有連詞，不能用it; which代表先行詞house在定語從句中作主語。）He was badly ill, and it made his mother worried. 他病了，那使他母親很擔心。（it指代他病了 ”這件事，注意and。）He was badly ill, which made his mother worried.（which代表前面整個主句，在定語從句中作主語）【高清課堂：Unit 3語法精講it做形式主語】it作形式主語it作形式主語和形式賓語時，一般稱為引導(dǎo)詞，引出特定的句型。it作形式主語，代替由不定式，動名詞或從句表示的真正主語。不定式、動名詞或從句都可

10、以作主語，如：To say is one thing, and to do is another. （不定式作主語）說是一回事，做是另一回事。Seeing is believing.眼見為實。（動名詞作主語）That he is a hero is true.（從句作主語）當主語過長時，就會有不平衡感，為了句子的平衡、美觀，我們引入了引導(dǎo)詞的概念。1）代替由不定式表示的真正主語句型：It is + adj. / n. +for/of sb. to do sth.It is impolite to talk loudly in public places.在公共場合大聲說話是不禮貌的。(it 代

11、替不定式to talk loudly in public places )為什么形容詞后有時用for,有時用of呢？仔細觀察這兩個句型：It is important (necessary, possible, impossible, easy, hard, difficult )for sb. to do sth.It is nice (cruel, kind, rude, wise, stupid, clever, foolish, polite )of sb. to do sth.我們可以得出這樣的結(jié)論：當形容詞只是修飾這件事時，用 for sb.,我們可以稱為“單層修飾”；如果形容詞看

12、上去是修飾人的，而且事情做出來也肯定是這樣的，即形容詞既修飾人，也修飾物時，用 of。例如：我們學(xué)英語很重要。Its important for us to learn English.important是修飾“我們”，還是修飾“學(xué)英語”這件事呢？修飾“學(xué)英語”這件事，所以 用 for。再如：你幫助我真好。Its very kind of you to help me.第一，“你”是好的；第二“幫助我”這件事也是好的，所以雙重修飾就用of。2)可代替動名詞表示的真正主語。Its no use crying over spilt milk. 覆水難收。Its no good taking in

13、much fat and sugar.吸收過多的脂肪和糖沒有好處。Its no fun watching the same movie for a second time. 同音日電影再看遍沒有意思。這里crying.等動名詞短語是真正的主語，it代替它們作形式主語。這些句型與前面的句型類似，那么什么時候要加-ing形式呢？我們只需記住，動名詞的這種句型是比較少的，記住一些固定用法即可，如在高考中經(jīng)常出現(xiàn)的Its no use/ no good/ no fun doing sth.做某事沒有用/沒有好處/沒有意思。3)代替主語從句Its a pity that I didn t think o

14、f it earlier. 我沒有早一點這么想真是遺憾。It is a well-known fact that smoking can cause cancer.吸煙會引起癌癥是盡人皆知的事實。it代替that引導(dǎo)的主語從句作形式主語。注意：選 it還是as：It is well known to all that the earth is round.眾所周知，地球是圓的。這個句子中it代替that引導(dǎo)的從句作形式主語，經(jīng)常會與下面這個定語從句的句型混淆：is well known to all, the earth is round.這個句子中，第一個典型特征是逗號，第二是逗號后沒有th

15、at,也就沒有形式主語了?？瞻滋帒?yīng)該填 As。As代替后面的句子the earth is round”,在定語從句中作主語。這兩種形式要清晰地記住。4)注意以下固定句型：It seems (ed) / appears (ed) that .彳以乎It (so) happened that . 碰巧.It turns (ed) out that. 結(jié)果是It occurred to sb. that .某人突然想起 It is said / reported / believed / hoped / well known / suggested . that.據(jù)說/據(jù)報道/大家都相信/人人都希望

16、/大家都知道/有人建議.例如：It so happened that the tickets were sold out. 碰巧票都賣光了。It occurred to her that she might adopt a homeless child.她想到她可以收養(yǎng)一個無家可歸的孩子。It turns out that the situation is quite serious. 結(jié)果表明情況很嚴峻。it用作形式賓語it作形式賓語，通常有這些特點：1 . it代替真正的賓語：不定式短語，動名詞短語或that引導(dǎo)的賓語從句作形式賓語；2 .賓語后常帶有形容詞或名詞作賓語補足語；3 .常用于

17、止匕句型動詞：make, think, consider, count （認為）,believe, guess, suppose, declare（宣布）,imagine, feel, find, discover, notice , regard （看作） 等。 例如：我們認為每天打掃教室是我們的職責。We think it our duty to clean our classroom every day.主語動詞形賓賓語補足語真正賓語常見句型：1 .動詞+ it+形容詞/名詞+ （for/of） +to do/從句I find it hard for you to do the task

18、 on your own.我發(fā)現(xiàn)靠你自己做這個工作很難。They found it difficult that they would finish their work in two days.他們發(fā)現(xiàn)他們很難在兩天內(nèi)完成工作。I made it a rule to keep diaries.寫日記成了我的習(xí)慣。2 .動詞+it+ no good/ no use / a waste of time /worth one s while 等 +doing.I ll make it worth your while telling me about his secret. 告訴我他的秘密，我會酬

19、謝你的。I believe it no use reading without understanding. 我認為讀書不理解沒用。3 .動詞 +it + 介詞短語 + thatowe it to sb. that 把歸功于take it for granted that 想當然/認為是當然的keep it in mind thatt己住:.We all take it for granted that Mile can succeed.我們都認為米爾能成功。We should always keep it in mind that no knowledge gained is ever wa

20、sted.我們要記住，沒有知識是白學(xué)的。4 . it用在不能直接跟賓語從句的動詞后面，尤其是表示好惡的動詞后，如：enjoy, like,love, dislike, hate, dont mind, be fond of, feel like, see to ,賓語從句緊跟 it 之后。I hate it you can swim so well and I can t.我嫉妒你游得這么好，而我不行。I hate it when people talk with their mouths full of food.我厭惡人們嘴里滿是食物時談話。I would appreciate it if

21、 you call back this afternoon for the doctor s appointment.如果你下午打電話預(yù)約醫(yī)生，我會很感激的。5 .介詞后一般不能直接跟賓語從句，常用 it,賓語從句跟it后（except that例外）。 Im for it that you will follow their advice.我贊成你聽從他們的建議。it常用的固定搭配1. make it在口語當中相當于 succeed,表示“成功、做到、說定、趕上、及時到達”等，或用于 約定時間。He never really made it as an actor.作為演員，他從沒成功過。

22、Shall we meet next week ?我們下周見好嗎？ OK. We just make it next Saturday.好。我們就定在下周六吧。2. as it is事實上，實際情況是；照原樣We had planned to finish the task today , but as it is we probably won t finish it until next week.我們原計劃今天完成這項工作，但實際上我們也許到下周才能完成。Leave the table as it is.桌子按原樣放著吧。3. if it werent for /if it hadnt

23、been for 如果不是,要不是If it werent for Tom , I wouldn t be alive today.如果不是湯姆，我不會活到今天的。4. thats it搞定、結(jié)束、到此為止、僅此而已；就是這樣，完全正確You can have one more sweet, and thats it.你可以再吃一塊糖，不能再多了。 一I guess the key to the problem is the choice A.我想這道題的答案是A。一Thats it.完全正確。5. Take it/things easy.不要慌，別擔心Take it easy! He will do it well. 別緊張，他會做好的。6. worth it好處，值得做Dont hesitate about it! Its worth it.別猶豫了，值得一做。7. Believe it or not.信不信由你Believe it or not , Tom is getting married to Mary next Sunday.信不信由你，湯姆和瑪麗下周結(jié)婚。8. take it or leave it要么接受要么放棄That is my last offer. You can take it or lea