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高中三年级英语

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  • 改错题
    短文改错。
    下面短文中有10处语言错误。请在有错误的地方增加、删除或修改某个单词。
    增加:在缺词处加一个漏字符号(∧),并在下面加上该加的词。
    删除:把多余的词用斜线()划掉。
    修改:在错的词下划一横线,并在该词下面写上修改后的词。
    注意:
    1.每处错误及其修改均仅限一词;
    2.只允许修改10处,多者(从第11处起)不计分。
    I like riding my bike. Though it is not very new, but it is my best friend. I find very convenient to go
    anywhere with a bike. Riding gives me not only exercises but also pleasure. I use my bike almost in
    summer when the weather is warm and dry. It can be very pleasant in winter when it is cold and rain is
    pour down. It can also be very dangerous. Of course I will be very carefully on my bike. In fact,
    accidents are not the only problem. Once I went  bookstore on my mother's bike to buy some books
    and come out to find the bike missing. Now I have two strong lock.
    ______________________________________________________________________________
    本题信息:2012年北京模拟题英语改错题难度较难 来源:姜雪
  • 本题答案
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本试题 “短文改错。下面短文中有10处语言错误。请在有错误的地方增加、删除或修改某个单词。增加:在缺词处加一个漏字符号(∧),并在下面加上该加的词。删除:把多余...” 主要考查您对

可数名词及其单复数

不可数名词

形容词

副词

介词和介词短语

情态动词

现在分词

一般过去时

状语从句

it的用法

等考点的理解。关于这些考点您可以点击下面的选项卡查看详细档案。
  • 可数名词及其单复数
  • 不可数名词
  • 形容词
  • 副词
  • 介词和介词短语
  • 情态动词
  • 现在分词
  • 一般过去时
  • 状语从句
  • it的用法

可数名词:

是指能以数目来计算,可以分成个体的人或东西;因此它有复数形式,当它的复数形式在句子中作主语时,句子的谓语也应用复数形式。 
                         


可数名词复数的规则变化: 

情况 构成方法  读音 例词
一般情况 加 –s 1.清辅音后读/s/;
2.浊辅音和元音后读/z/; 
map-maps
bag-bags
car-cars
以s,sh,ch,x等结尾的词 加 -es 读 /iz/ bus-buses
watch-watches
以ce,se,ze,(d)ge等结尾
的词 
加 -s 读 /iz/  license-licenses
以辅音字母+y结尾的词   变y 为i再加es  读 /z/ baby-babies
另外:
1)以y 结尾的专有名词,或元音字母+y结尾的名词变复数时,直接加s变复数: 
如:two Marys the Henrys      monkey---monkeys holiday---holidays  
比较:层楼:storey---storeys  story---stories
2)以o 结尾的名词,变复数时:
a. 加s,如: photo---photos  piano---pianos 
b. 加es,如:potato--potatoes tomato--tomatoes
c. 均可,如:zero---zeros / zeroes 
3)以f或fe 结尾的名词变复数时:
a. 加s,如: belief---beliefs roof---roofs   safe---safes  gulf---gulfs;
b. 去f, fe 加ves,如:half---halves knife---knives leaf---leaves wolf---wolves  wife---wives life---lives thief---thieves;
c. 均可,如:handkerchief:  handkerchiefs / handkerchieves

可数名词复数的不规则变化:

1)child---children foot---feet  tooth---teeth   mouse---mice  man---men woman---women  
注意:与 man 和 woman构成的合成词,其复数形式也是 -men 和-women。 
如:an Englishman,two Englishmen. 但German不是合成词,故复数形式为Germans;Bowman是姓,其复数是the Bowmans。
2)单复同形 如:
deer,sheep,fish,Chinese,Japanese
li,jin,yuan,two li,three mu,four jin 
但除人民币元、角、分外,美元、英镑、法郎等都有复数形式。如:
   a dollar, two dollars;  a meter, two meters
3)集体名词,以单数形式出现,但实为复数。
如:staff  people police cattle 等本身就是复数,不能说a staff  a people,a police,a cattle,
但可以说a person,a policeman,a head of cattle, the English,the British,the French,the Chinese,the
Japanese, the Swiss 等名词,表示国民总称时,作复数用。 
如:The Chinese are industries and brave. 中国人民是勤劳勇敢的。
4)以s 结尾,仍为单数的名词,如:
a. maths,politics,physics等学科名词,为不可数名词,是单数。
b. news 是不可数名词。
c. the United States,the United Nations 应视为单数。
The United Nations was organized in 1945. 联合国是1945年组建起来的。
d. 以复数形式出现的书名,剧名,报纸,杂志名,也可视为单数。
 "The Arabian Nights" is a very interesting story-book.
 <<一千零一夜>>是一本非常有趣的故事书。
5) 表示由两部分构成的东西,如:glasses (眼镜) trousers, clothes ;
若表达具体数目,要借助数量词 pair(对,双); suit(套); a pair of glasses; two pairs of trousers
6)另外还有一些名词,其复数形式有时可表示特别意思,如:goods货物,waters水域,fishes(各种)鱼

复合名词的复数形式:
   名词作定语名词作定语一般用单数,但也有以下例外。
1)用复数作定语。
如:sports meeting 运动会 
students reading-room 学生阅览室  
talks table 谈判桌    
the foreign languages department 外语系
2)man, woman, gentleman等作定语时,其单复数以所修饰的名词的单复数而定。
如:men workers  
women teachers 
gentlemen officials
3)有些原有s结尾的名词,作定语时,s保留。
如:goods train (货车) 
arms produce 武器生产
customs papers 海关文件
clothes brush衣刷
4)数词+名词作定语时,这个名词一般保留单数形式。
如:two-dozen eggs 两打/(二十四个鸡蛋) 
a ten-mile walk 十里路 
two-hundred trees 两百棵树           
a five-year plan 一个五年计划   

可数名词单复数知识体系:

 


不同国籍人的单复数:

国籍 总称(谓语用复数) 单数 复数
中国人 the Chinese a Chinese  two Chinese
瑞士人 the Swiss a Swiss two Swiss
澳大利亚人 the Australians  an Australian two Australians
俄国人 the Russians a Russian two Russians
意大利人 the Italians an Italian two Italians
希腊人 the Greek a Greek two Greeks
法国人 the French a Frenchman two Frenchmen
日本人 the Japanese a Japanese two Japanese
美国人 the Americans an American two Americans
印度人 the Indians an Indian two Indians
加拿大人 the Canadians a Canadian two Canadians
德国人 the Germans a German two Germans
英国人 the English an Englishman two Englishmen
瑞典人 the Swedish a Swede two Swedes


不可数名词的概念:

不可数名词是指不能以数目来计算,不可以分成个体的概念、状态、品质、感情或表示物质材料的东西;它一般没有复数形式,只有单数形式,它的前面不能用不定冠词a / an ,若要表示它的个体意义 时,一般要与一个名词短语连用。
例如: a cup of tea 一杯茶
             a piece of news 一则新闻 
             two pieces of paper 两张纸  


不可数名词量的表示:

1)物质名词:
a. 当物质名词转化为个体名词时。
比较:Cake is a kind of food. 蛋糕是一种食物。(不可数)
            These cakes are sweet. 这些蛋糕很好吃。(可数)
b. 当物质名词表示该物质的种类时,名词可数。
Thisfactoryproducessteel.(不可数)
如:We need various steels. (可数)
c. 当物质名词表示份数时,可数。
如:Our country is famous for tea. 我国因茶叶而闻名。 
        Two teas, please.  请来两杯茶。
2)抽象名词有时也可数。
如:four freedoms 四大自由
        the four modernizations 四个现代化
注:物质名词和抽象名词可以借助单位词表一定的数量。
如:a glass of water 一杯水 
        a piece o fadvice 一条建议


不可数名词用法:

1、不可数名词前不能直接加数词或a(an)。切忌犯以下错误: meat, two tea, 应说a piece of meat, two cups oftea。
2、不可数名词无单复数变化,谓语动词一般用单数形式。
如:There is some milk in the glass. 杯里有一些牛奶。
        Some food on the table goes bad. 桌子上的食物变质了。
3、能修饰不可数名词的词有:much, a little, little, a bit, some, any, a lot of, plenty of等,以此来表示不确定的数量。如:
        much bread 许多面包
        a little milk 一点牛奶
        a lot of work 许多工作
4、表示具体的数量时应用单位词加of结构。
如:I bought two kilos of meat. 我买了两公斤肉。
       He ate three pieces of bread. 他吃了三块面包。
       Would you like a cup of coffee? 你想喝杯咖啡吗?


形容词的概念:

形容词(adjective),简称adj.或a,形容词用来修饰名词或代词,表示人或事物的性质、状态,和特征的程度好坏与否,形容词在句中作定语、表语、宾语补足语。通常,可将形容词分成性质形容词和叙述形容词两类,其位置不一定都放在名词前面。


形容词的作用与位置:

形容词是用来修饰名词的,常被放在名词前作定语,或放在系动词后面作表语。以下属几种特殊情况,须牢记;
(1)形容词短语作定语,定语后置。
如:a language difficult to master,
        a leaning tower about 180 feet high
(2)表语形容词(afraid、alike、alone、asleep、awake、alive等)作定语,定语后置。如a man alive。有些表身体健康状况的形容词如well、faint、ill只作表语。sick既可作表语又可作定语,ill如作定语意为“bad”。
(3)用作定语,修饰由不定代词one、no、any、some和every构成的复合词如anything、something等时,通常后置。
如:I have something important to tell you.
(4)else常用作疑问代词和不定代词的后置定语。
(5)enough、nearby修饰名词前置或后置,程度副词一般位于形容词、副词前面,enough修饰形容词、副词时,必须后置。
(6)几个并列的形容词作定语,其语序通常为:限定语(The、A)+描绘性形容词+size(大小)+shape(形状)+age(年龄、时间)+color(颜色)+origin(国籍、来源)+material(材料)+purpose(目的)+名词。

口诀:
限定描绘大长高,形状年龄和新老;颜色国籍跟材料,作用类别往后靠。
如:a heavy black Chinese steel umbrella,
        the man's first tow interesting little red French oil paintings


形容词的用法:

1、形容词修饰名词,说明事物或人的性质或特征。通常,可将形容词分成性质形容词和叙述形容词两类,其位置不一定都放在名词前面:
1)直接说明事物的性质或特征的形容词是性质形容词,它有级的变化,可以用程度副词修饰,在句中可作定语、表语和补语。例如:hot热的。
2)叙述形容词只能作表语,所以又称为表语形容词。这类形容词没有级的变化,也不可用程度副词修饰。
大多数以a开头的形容词都属于这一类。例如:
afraid害怕的。(错)Heisanillman. (对)Themanisill. (错)Sheisanafraidgirl. (对)Thegirlisafraid.
这类词还有:well,unwell,ill,faint,afraid,alike,alive,alone,asleep,awake等。
3)形容词作定语修饰名词时,要放在名词的前边。但是如果形容词修饰以-thing为字尾的词语时,要放在这些词之后。例如:somethingnice

2、用形容词表示类别和整体:
1)某些形容词加上定冠词可以泛指一类人,与谓语动词的复数连接。如:the dead,the living,the rich,the poor,the blind,the hungry The poorarelosinghope.穷人失去了希望。
2)有关国家和民族的形容词加上定冠词指这个民族的整体,与动词的复数连用。如:the British,the English,the French,the Chinese. The English have wonderful senseofhumor.

以-ly结尾的形容词:
1)大部分形容词加-ly可构成副词。但friendly,deadly,lovely,lonely,likely,lively,ugly,brotherly,仍为形容词。改错:
如:(错)She sang lovely.
        (错)He spoke to me very friendly.
        (对)Her singing was lovely.
        (对)He spoke to me in a very friendly way.
2)有些以-ly结尾既为形容词,也为副词。 daily,weekly,monthly,yearly,early .
如:The Times is a daily paper. 
        The Times is published daily.


形容词知识体系:

 


复合形容词的构成

(1)形容词+名词+ed:
          如:kind-hearted 好心的,white-haired 白发的
(2)形容词+形容词:
          如:red-hot 炽热的,dark-blue 深蓝的
(3)形容词+现在分词:
          如:good-looking 好看的,easy-going 随和的
(4)副词+现在分词:
          如:hard-working 勤劳的,fast-moving 快速转动的
(5)副词+过去分词:
          如:hard-won 得来不易的,newly-made 新建的
(6)名词+形容词:
          如:life-long 终生的,world-famous 世界闻名的
(7)名词+现在分词:
          如:peace-loving 爱好和平的,fun-loving 爱开玩笑的
(8)名词+过去分词:
          如:snow-covered 白雪覆盖的,hand-made 手工的
(9)数词+名词+ed:
          如:four-storeyed 4层楼的,three-legged 3条腿的
(10)数词+名词(名词用单数):
          如:ten-year 10年的,  two-man 两人的


副词的概念:

副词是指在句子中表示行为或状态特征的词,用来修饰动词、形容词、其他副词、介词短语、非谓语动词乃至整个句子,表示时间、地点、程度、方式等概念。


副词的位置:

1)在动词之前。
2)在be动词、助动词之后。
3)多个助动词时,副词一般放在第一个助动词后。
注意:
a. 大多数方式副词位于句尾,但宾语过长,副词可以提前,以使句子平衡。
如:We could see very clearly a strange light ahead of us.
b. 方式副词well,badly糟、坏,hard等只放在句尾。
如:He speaks English well.

副词的排列顺序:

1)时间,地点副词,小单位的在前,大单位在后。
2)方式副词,短的在前,长的在后,并用and或but等连词连接。
如:Please write slowly and carefully.
3)多个不同副词排列:程度+地点+方式+时间副词。
注意:副词very可以修饰形容词,但不能修饰动词。
改错:(错)I very like English.
            (对)I like English very much.
注意:副词enough要放在形容词的后面,形容词enough放在名词前后都可。
如:I don't know him well enough. 
        There is enough food for everyone to eat.
        There is food enough for everyone to eat.


兼有两种形式的副词:

1)close与closely:
      close意思是“近”;closely意思是“仔细地”。
      如: He is sitting close to me.
               Watch him closely.
2)late与lately:
      late意思是"晚";lately意思是“最近” 。
      如:You have come too late. 
              What have you been doing lately?
3)deep与deeply:
      deep意思是“深”,表示空间深度;deeply时常表示感情上的深度,“深深地” 。
      如:He pushed the stick deep into the mud. 
              Even father was deeply moved by the film.
4)high与highly:
      high表示空间高度;highly表示程度,相当于much。
      如:The plane was flying high.
              I think highly of your opinion.
5)wide与widely:
      wide表示空间宽度;widely意思是“广泛地”,“在许多地方”。
      如:He opened the door wide.
              English is widely used in the world.
6)free与freely:
      free的意思是“免费”;freely的意思是“无限制地”。
      如:You can eat free in my restaurant whenever you like. 
              You may speak freely, say what you like.


副词知识体系:


介词和介词短语的概念:

介词是一种用来表示词与词、词与句之间的关系的虚词,在句中不能单独作句子成分。介词后面一般有名词、代词或相当于名词的其他词类,短语或从句作它的宾语。介词和它的宾语构成介词词组,在句中作状语,表语,补语或介词宾语。介词可以分为时间介词、地点介词、方式介词和其他介词。


误用介词的三种情况:

1、多用介词:
多用介词可能是受汉语意思的影响将及物动词误用作不及物动词,也可能是受相关结构的影响而用错:
误:We discussed about the plan.
正:We discussed the plan. 我们讨论了计划。
误:Did he mention about the accident?
正:Did he mention the accident? 他提到那次事故了吗?
误:I saw her enter into the bank.
正:I saw her enter the bank. 我看见她进了银行。
误:He married with[to] a nurse.
正:He married a nurse. 他同一位护士结了婚。
误:How can contact with you?
正:How can contact you? 我怎么与你联系?
误:We should serve for the people heart and soul.
正:We should serve the people heart and soul. 我们应该全心全意地为人民服务。
误:Who controls over the factory? (但名词control可接over)
正:Who controls the factory? 谁管理这个工厂?
误:He has a great many of friends here. (比较a great number of)
正:He has a great many friends here. 他在这儿有很多朋友。

2、漏用介词:
漏用介词可能是受汉语意思的影响将不及物动词误用作及物动词,或是受相关结构的影响的影响而用错等:
误:This matter is difficult to deal. (deal with=处理)
正:This matter is difficult to deal with. 这事很难处理。
误:He is not a man to be depended.
正:He is not a man to be depended on. 他不是个可靠的人。
误:He took a cup of tea, and went on the story.
正:He took a cup of tea, and wentonwiththestory.他喝了一口茶,又接着讲故事。
误:My mother still regards me a child. (比较consider…as中的as可省略)
正:My mother still regards me as a child. 我母亲还把我当小孩看。
误:They insisted sending a car over to fetch us.
正:They insisted on sending a car over to fetch us.他们坚持要派车来接我们。
误:What he says is worth listening.
正:What he said is worth listening to.他的话值得一听。

3、错用介词:
错用介词的情况比较复杂,可能是因受汉语意思的而错,也可能是因弄不清搭配关系而错,可能是混淆用法而错,也可能是受相关结构的影响而错,可能是忽略语境而错,也可能是想当然的用错:
误:She called on his office yesterday. (call on+人,call at+地点)
正:She called at his office yesterday. 她昨天去了他办公室拜访。
误:He is engaged with a nurse.
正:He is engaged to a nurse.他与一位护士订了婚。
误:The sun rises from the east.
正:The sun rises in the east.太阳从东方升起。
误:Under his help, I finished it in time.
正:With his help, I finished it in time. 在他的帮助下,我及时做完了。
误:During he was in Japan, he visited many places.
正:During his stay in Japan, he visited many places.他在日本期间,参观过许多地方。
误:We are familiar to his character.
正:We are familiar with his character.我们了解他的性格。
误:Help yourself with the fruit.
正:Help yourself to the fruit.吃点水果吧。


介词的宾语:

 1、名词或代词作介词宾语:
如:Are you interested in history? 你对历史感兴趣吗?
        Don't worry about it. 别为它担心。
注:若是人称代词用作介词宾语,要注意用宾格。
如:No one can sing like her. 没有人能像她那样唱歌。(不能用like she)
2、动名词作介词宾语:
如:He is good at telling stories. 他善于讲故事。 
        In crossing the street he was run over. 他在穿过马路时被汽车撞倒。
3、过去分词作介词宾语:
如:We can't regard the matter as settled. 我们不能认为这事已经解决。
        I take it for granted you have read the book. 我以为你读过这本书。
:过去分词用作介词宾语通常只见于某些固定结构中,如上面第1句涉及regard…as(认为…是)结构,第2句涉及take sth for granted(认为某事属实)。在其他情况下,介词后通常不直接跟过去分词作宾语,若语义上需要接过去分词(表被动),可换用“being+过去分词”:
如:He went out without being seen by the others.他出去了,没有被其他人看见。
4、从句作介词宾语:
如:He was not satisfied with what she said. 他对她说的不满意。
        I'm worried about where he is. 我担心他上哪儿去了。
:介词后通常不接that从句,遇此情况需考虑用其他结构:
误:He paid no attention to that she was poor.
正:He paid no attention to the fact that she was poor. 他根本不注意她很穷这一事实。
但有个别介词(如except)可接that从句。
比较:I know nothing about him except that he lives next door./I know nothing about him except for the fact that he lives next door. 我只知道他住在隔壁,其它的就不知道了。
5、不定式作介词宾语:
如:I had no choice but to wait. 除了等,我没有别的选择。 
       He wanted nothing but to stay there. 他只想留在那儿。
       They did nothing but complain. 他们老是一个劲地抱怨。 
       He never did anything but watch TV. 除了看电视,他从不干任何事。
:(1)介词后接不定式的情形通常只见于but, except等极个别个词。该不定式有时带to,有时不带to,其区别是:若其前出现了动词do,其后的不定式通常不带to;
若其前没有出现动词do,则其后的不定式通常带to。 
(2)介词后虽然通常不直接跟不定式作宾语,但却可接“连接代词(副词)+不定式”结构:
如:He gave me some advice on how to do it. 对于如何做这事他给我提了些建议。
6、形容词作介词宾语:
如:Her pronunciation is far from perfect. 她的语音远不是完美的。
        In short, we must be prepared. 总而言之,我们要有准备。
        Things have gone from bad to worse. 事情越来越糟。
:(1)有些形容词用作介词宾语可视为其前省略了动名词being:
如:He regarded the situationas(being) serious. 他认为形势严重。
        His work is far from(being) satisfactory. 他的工作丝毫不令人满意。 
(2)有些“介词+形容词”的结构已构成固定搭配:in full全部地,全面地,无省略地; in private私下地,秘密地; in particular特别地;in general一般地,通常地,概括地; in brief 简言之;in short总之,简言之; in vain徒然地,徒劳无益地;for fee免费地,无偿地; for certain肯定地,确切地;for sure肯定地,确切地; for short为了简短,简称;atl arge自由自在地,逍遥法外; by far…得多
7、副词作介词宾语:
如:I can't stay for long. 我不能久呆。 
        It's too hot in here. 这里面太热了。
        I looked every where except there. 除了那儿,我到处都看过了。
8、数词作介词宾语:
如:The city has a population of four million. 这座城市有四百万人口。
        He was among the first to arrive. 他是第一批到的。
9、介词短语作介词宾语:
如:Choose a book from among these. 从这些书中选一本吧。
        I saw her from across the street. 我从街的对面望见了她。
:通常可后接介词短语作宾语的介词是from, till, until, since, except, instead of等。
比较:I took it from the bed. 我从床那儿(或床上)拿的。
            I took it from under the bed. 我从床下拿的。 
10、复合结构用作介词宾语:
如:She had no objection to Mary marrying him. 她不反对玛丽与他结婚。
        She came in with a book in her hand. 她手里拿着一本书走了进来。
        All the afternoon he worked with the door locked. 整个下午他都锁着门在房里工作。

介词短语的句法功能:
1、表语:
如:He was with a friend. 他和一个朋友在一起。
        Health is above wealth. 健康胜过财富。
        This knife is for cutting bread. 这把小刀是用于切面包的。
:有些介词(如because of)引出的短语通常只用作状语,不用作表语:
误:His absence is because of the rain.
正:His absence is due to the rain. 他因雨未来。
但是,若主语是代词(不是名词),becauseof引出的短语可用作表语:
如:It is because of hard work. 那是因为辛苦工作的原因。
2、状语:
如:Don't touch it with your hands. 别用手去摸它。
        Did you do this by design or by accident? 你这样做是有意的还是无意的?
3、定语:
如:This is his reply to your letter. 这是他给你的回信。
        This is the best way of doing it. 这是做此事最好的方法。
        My love for you is deeper than the sea. 我对你的爱比海深。
4、宾语补足语:
如:I found everythingin good condition. 我发现一切正常。
       Her illness kept her in bed for a week. 她因生病在床上躺了一星期。
:用作宾语补足语的介词短语在相应的被动语态中则为主语补足语:
如:He was regarded as a hero. 他被看成是英雄。
5、宾语:
如:A man stepped out from behind the wall. 一个人从墙后走出来。
        He cannot spare anytime except on Sunday. 除星期日外,他抽不出时间。
6、主语:
如:Between6 and 7 suits me. 六点到七点对我比较适合。
        After the exams is the time to relax. 考试后是轻松一下的时间。
:介词短语通常不用作主语,尽管有时也像上面这样用作主语,但通常可视为是在一定的上下文中有所省略:
如:—When are we going to have the next meeting? 我们下次什么时候见面?
        —On Tuesday may be convenient. 星期二可能比较方便。
此句中onTuesday虽用作主语,但可视为是其前省略了meeting一词:
即:Meeting during the vacation may be convenient.


情态动词的概念:

情态动词表示说话人对某一动作或状态的态度。


几组词的辨析

1、need和dare的用法:
need和dare既可用作情态动词,也可用作实义动词。用作情态动词时,主要用于否定句和疑问句。用作实义动词时,可用于各种句式。
(1)用作情态动词:
 如:—Need I come? 我需要来吗?
         —Yes, you must. 需要。
         You needn′t telephone him now. 你现在不必打电话给他。 
         I don′t think you need worry. 我想你不必发愁。 
         She dare not go out alone at night. 她晚上不敢一个人出去。
         How dare you say I′m unfair? 你竟敢说我不公平?
         Not one of them dared mention this.他们谁也不敢提这件事。
(2)用作实义动词:
如:You don′t need to do it yourself. 你不必亲自做这件事。
        We need to tell them the news. 我们需要把这消息告诉他们。
        The table needs painting(to be painted.). 桌子需要油漆一下。
        We should dare to give our own opinion.我们要敢于提出自己的观点。
        He did not dare(to) look up. 他不敢抬头看。
        I dare day he′ll come again. 我想他会再来的。
2、can和be able to:
(1)情态动词can只有两种时态形式,现在式can和过去式could,而be able to有多种时态形式。
如:Mary can play the piano. She has been able to play it since she was 5. 玛丽会弹钢琴。她五岁起就会弹了。
(2)用在过去时中,could经常表示能够做某事,事实上不一定去做,而was∕were able to则表示“过去做成了某事”。在否定句中两者可通用。
如:He could swim across the English Channel. But he didn′t feel like it that day.
        他能游过英吉利海峡,但那天他不想游。
        Yesterday I was able to get home before the heavy rain. 昨天我在下大雨前赶到了家里。
3、must和have to:
must表示主观意志,而have to表示由于客观因素不得不做某事。must没有过去式,除在间接引语中可用于表示过去时间,在直接引语中表示过去时间应该用had to代替。
如:I told her that she must give up smoking. 我叫她必须戒烟。
        We had to get everything ready that night. 我们那晚得把一切准备就绪。
4、would和used to:
(1)usedto表示过去与现在或过去某时与后来的情况有不同,而would只表过去的情况。
如:People used to think that the earth was flat.  过去人们认为地球是平的。(现在人们不这么认为。) 
        She would go out for a walk in the morning when she was in the country.
        在乡下时,她总是在早晨去散会儿步。(可能现在仍有散步的习惯。)
(2)used to可表示过去的习惯动作和经常的情况,而would只表示过去的习惯动作。
如:He used to∕would smoke while writing. 过去他写东西时常抽烟。
        She used to be fat. 她过去很胖。


情态动词的基本用法:

1、can(could):
1)表示能力,could主要指过去时间。
如:Two eyes can see more than one. 两只眼比一只眼看得清。
        Could the girl read before she went to school? 这女孩上学前能识字吗?
2)表示可能(理论上或是逻辑判断上)。
如:The temperature can fall to–60℃, that is 60℃ below freezing. 气温可降至-60℃,也就是零下60℃。
        He can′t(couldn′t) have enough money for a new car. 他不可能有足够的钱买新车。  
        You mustn′t smoke while you′re walking around in the wood. You could start a fire. 
        在林子里走时勿吸烟,那样可能会引起火灾。
3)表示允许。
如:Can I have a look at your new pen? 我可以看一看你的新钢笔吗?
        He asked whether he could take the book out of the reading-room. 他问他可不可以把书带出阅览室。
4)表惊异、怀疑、不相信等态度。主要用于否定句、疑问句或感叹句中。
如:Where can(could) they have gone to? 他们会去哪儿了呢?
        He can′t(couldn′t) be over sixty. 他不可能超过六十岁。
        How can you be so careless? 你怎么这么粗心?
5)比较委婉客气地提出问题或陈述看法。
如:Can(Could) you lend me a hand? 帮我一把好吗?
        I′m afraid we couldn′t give you an answer today. 恐怕我们今天不能给你答复。
2、may(might):
1)表允许,might可以指过去时间,也可指现在时间,语气更委婉。
如:You may take what ever you like. 你喜欢什么就拿什么。
        He told me that I might smoke in the room. 他告诉我可以在房间里抽烟。
        May(Might) I ask for a photo of your baby? 我可以要一张你宝宝的照片吗?
在回答以may引起的问句时,多避免用这个词,而用其它方式:
如:Yes, please./Certainly. /Please don′t./You′d better not./No, you mustn′t.等,以免显得太严峻或不客气。
2)表可能(事实上)。可以指过去时间,也可以指现在时间,但语气更加不肯定。
如:He may be at home. 他可能在家。
        She may not know about it. 她可能不知道这件事。
        He was afraid they might not agree with him. 他担心他们可能不同意他的意见。 
如:They might be having a meeting, but I′m not sure. 他们有可能在开会,不过我不肯定。
3、must:
1)表示义务。意为“必须”(主观意志)。
如:We must do everything step by step. 我们一切都必须循序渐进地做。
        You mustn′t talk to her like that. 你不可能那样对她说话。
         —Must we hand in our exercise-books now? 我们现在就要交练习本吗?
         —No, you needn′t./No, you don′t have to.不必。(这种情况下,一般不用mustn′t)
2)表示揣测。意为“想必、准是、一定”等,只用于肯定句。
如:He must be ill. He looks so pale. 他准是病了。他的脸色苍白。
如:She′s wearing a diamond necklace. She must have a lot o fmoney. 她戴着钻石项链,一定很有钱。
4、shall:
1)表征询意见,用于第一、第三人称疑问句。
如:Shall I get you some tea? 我给你点茶好吗?
        Shall the boy wait outside? 让那男孩在外面等吗?
        What shall we do this evening? 我们今晚做什么?
2)表说话人的意愿,有“命令、允诺、警告、决心”等意思,用于第二、第三人称陈述句。
如:You shall do as I say. 按我说的做。(命令)
        You shall have my answer tomorrow. 你明天可以得到我的答复。(允诺)
        He shall be sorry for it one day, I tell you.有一天他会后悔的,我告诉你。(警告)
如:Nothing shall stop us from carrying out the plan.什么也不能阻止我们执行这项计划。(决心)
5、will:
1)表意愿,用于各种人称陈述句。
如:I will do anything for you. 我愿为你做任何事。
        None is so blind as those who won′t see. 不愿看的人眼最瞎。
        If you will read the book, I′ll lend it to you. 如果你愿意读这本书,我会把它借给你。
2)表请求,用于疑问句。
如:Will you close the window? It′s a bit cold. 请你把窗户关上好吗?有点冷。
        Won′t you drink some more coffee? 再来一点咖啡好吗?
3)表示某种倾向或习惯性动作。
如:Fish will die out of water. 鱼离开水就不能活。
        The door won′t open. 这门打不开。
        The boy will sit there hour after hour looking at the traffic go by. 
        那男孩常常坐在那里好几个钟点,看着车辆行人通过。
6、should:
1)表义务。意为“应该”(某件事宜于做),用于各种人称。
如:You should be polite to your teachers. 你对老师应该有礼貌。
        You shouldn′t waste anytime. 你不应该浪费时间。
2)表推测,意为“想必一定、照说应该、估计”等。
如:The film should be very good as it is starring first-class actors. 这部新电影是一流演员主演的,估计拍得很好。       
        They should be home by now. 照说他们现在应当已经到家了。
7、would:
1)表意愿。
如:They would not let him in because he was poorly dressed. 他们不让他进去因为他衣着破旧。 
        I said I would do anything for you. 我说过我愿意为你做任何事。
2)表委婉地提出请求、建议或看法。
如:Would you like another glass of beer? 再来杯啤酒好吗?
        Would you mind cleaning the window? 请把窗户擦一下好吗?
        They wouldn′t have anything against it. 他们不会有什么反对意见。
3)表过去反复发生的动作或过去的一种倾向。
如:Every time she was in trouble, she would go to him for help. 她每遇到麻烦都会向她求助。
8、ought to:
1)表义务,意为“应该”(因责任、义务等该做),口气比should稍重。
如:You are his father. You ought to take care of him. 你是他父亲,应当管他。
        You oughtn′t to smoke so much. 你不应该抽这么多烟。
2)表推测,暗含很大的可能,语气较弱。
如:Han Mei ought to know his telephone number. 韩梅该知道他的电话号码。
        There′s a fine sun set; it ought to be a fine day tomorrow. 今天有晚霞,明天应该是个好天。
9、used to:
表示过去的习惯动作或状态,现在不复发生或存在。疑问式和否定式有两种。
如:He used to live in the countryside, but now he lives in the city. 他过去住在乡下,现在住在城里。
        There used to be a building at the street corner, but it has been pulled down. 街道拐角处过去有座楼房,现在拆了。
        I usedn′t (didn′t use) to smoke. 我过去不抽烟。
        Used you(Did you use) to go to school on foot? 你过去常步行去学校吗?

情态动词的其他用法:

首先它是动词,而且不同于行为动词,行为动词表示的是可以通过行为来表达的动作(如写,读,跑),而情态动词只是表达的一种想法(如能,也许,敢)。
用法是:情态动词+行为动词原形:
句:I can read this sentence in English. 我能用英语读这句话。
情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语,只能和其他动词原形构成谓语。
如:We can be there on time tomorrow. 我们明天能按时去那儿。
        May I have your name? 我能知道你的名字吗?
        Shall we begin now? 我们现在就开始吗?
        You must obey the school rules. 你必须遵守校规。


情态动词知识体系:

 


情态动词表推测的三种句式:

1、在肯定句中一般用must(一定),may(可能),might/could(也许,或许)。
如:He must/may/might know the answer to this question? 他一定/可能/也许知道这个问题的答案。 
        It is cold in the room. They must have turned off the heating. 屋里很冷,他们肯定把暖气关了。
2、否定句中用can't/couldn't (不可能), may not/might not(可能不)。
如:It can't/couldn't be the headmaster. He has gone to America.  这不可能是校长,他去美国了
        He may not/might not know the scientist. 他也许不认识那位科学家。
3、疑问句中用can/could(能……?)。
如:Could he have finished the task? 他可能把任务完成了吗?
        Can he be at home now? 他现在能在家吗?
注:以上三种句式中情态动词的语气按程度都是依次递减的。Might, could并非may, can的过去式,而表示语气较为委婉或可能性较小。

情态动词表推测的三种时态:

1、对将来情况的推测,用“情态动词+动词原形”。
如:She must/may/might/could arrive before 5.  5:00前她一定/可能/也许到。
        She must/may/might/could walk miles and miles among the hills without meeting anyone.
        她一定/可能/也许会在山里一连走好几英里而遇不到一个人。
2、对现在或一般情况的推测,用“情态动词+be”,“情态动词+bedoing”或“情态动词+动词原形”。
如:He must/may/might/could be listening to the radio now. 他一定/可能/也许正在听收音机。
        He can't(couldn't)/may(might) not be at home at this time. 这个时候他不可能/可能不在家。
        Mr. Bush is on time for everything. How can(could) he be late for the opening ceremony?
        布什先生一向准时,这次开幕式他怎么可能迟到呢?
3、对过去情况的推测,用“情态动词+have+过去分词”。
如:It must/may/might/ could have rained last night. The ground is wet. 地湿了,昨晚肯定/可能/也许下雨了。
        The door was locked. He can(could) not/may(might) not have been at home. 门锁着,他不可能/可能不在家。       
        Can/Could he have gotten the book?难道他找到书了吗?
:情态动词should/ought to表推测时,意为“想必会,理应……”但与“have+过去分词”连用时,则又可构成虚拟语气意为“本应该做某事却没做”。
如:It's seven o'clock. Jack should/ought to be here at any moment.
        现在七点钟了,杰克理应随时到达。(推测)    
        She should/ought to have attended your birthday party, but she had to look after her mother in hospital.(虚拟)
        她本该出席你的生日晚会的,可是她得在医院照顾她妈妈。 
        Tom should not/ought not to have told me your secret, but he meant no harm.(虚拟)
        汤姆本不该告诉我你的秘密,可是他并无恶意。

现在分词的概念:

现在分词(PresentParticiple)(又称-ing形式),是分词的一种,是非限定动词,即在句子里面不能单独充当谓语,但能充当其它的一些成分(定语,表语,补语和状语)。一般式:doing;一般被动式:being done;完成式:having done;完成被动式:having been done。所有否定式都是在-ing前面加not。


现在分词的用法:

1)做表语:
如:He was very amusing.
        That book was rather boring.
很多动词的现在分词都可以作表语:exciting, interesting, encouraging, disappointing, confusing, touching, puzzling.
2)作定语:
上面所出现的现在分词都可以用作定语,修饰一个名词:
如:That must have been a terrifying experience.
        I found him a charming person.
现在分词短语还可以放在名词的后面修饰名词,相当于一个定语从句:
如:There are a few boys swimming in the river.
        There is a car waiting outside.
3)作状语:
现在分词短语可以表示一个同时发生的次要的或伴随的动作:
如:Following Tom, we started to climb the mountain. 
        Opening the drawer, he took out a box.
        Taking a key out of his pocket, he opened the door.
现在分词短语还可以表示原因,相当于一个原因状语从句:
如:Not knowing her address, we couldn't get in touch with her.
        Being unemployed, he hasn't got much money.
现在分词短语还可以表示时间,相当于一个时间状语从句:
如:Hearing the news, they all jumped with joy.
        Returning home, he began to do his homework. 
        Jim hurt his arm while playing tennis.
        Be careful when crossing the road.
        Having found a hotel, we looked for some where to have dinner.
        Having finished her work, she went home.
4)作宾补:
现在分词在一些动词之后可以做宾语的补语:
例如:see, hear, catch, find, keep, have等。
如:I see him passing my house every day.
        I caught him stealing things in that shop.
        I smelt something burning.
        She kept him working all day.


现在分词其他用法解析:

1、现在分词一般式的用法:
现在分词的一般式所表示的动作与主语动作同时发生:
如:When we arrived, we found him sleeping. 我们到达时发现他在睡觉。
         Living in the 示的动作也可略早于或迟于谓语动作,但两者之间没有时间间隔:
如:Seeing nobody at home, he decided to leave a note. 发现没有在家,他决定留个字条。 
         He went home, finding the door locked. 他回到家,发现门是锁着的。当现在分词所表示的动作略迟于谓语动作时,现在分词通常位于句末。

2、现在分词完成式的用法:
现在分词的完成式主要表示发生在谓语动作之前的动作:
如:Having been there once, she knew the place quite well. 由于去过那儿一次,她对那地方很熟悉。
        Having failed twice, he didn't want to try again. 他已经失败了两次,不想再试了。
注:(1)现在分词的一般式和完成式均可表示已完成或先于谓语的动作,但有区别:现在分词所表示的动作虽然可以先于谓语动作,但两者之间没有时间间隔,而现在分词的完成式所表示先于谓语的动作则与谓语动作有一定的时间间隔:
如:Locking the door, he went out. 锁好门之后,他就出去了。
        Having invited him here to speak, we'd better go to his lecture. 既然我们请了他来作报告,我们最好去听一下。
有时即使是分词动作与谓语动作几乎同时发生,但如果要强调分词动作的完成性,也应用现在分词的完成式:
如:Having bought our tickets, we went into the theatre. 我们买好票后就走进剧场。
(2)现在分词的完成式一般不用作定语:
误:Do you know anyone having lost a cat? 你知道有谁丢了一只猫吗?
误:I want to talk to the person having broken the window. 我想同打破窗户的人谈谈。
若将以上现分词的完成式改为一般式也不可以(因为现在分词作后置定语时通常只表示与谓语动作同时或几乎同时发生的动作,而不能先于谓语动作而发生):
误:I want to talk to the person breaking the window.

3、现在分词被动式的用法:
当要表示一个被动动作时,现在分词就用被动形式。现在分词的一般式和完成式均有被动式形式:
(1)现在分词一般式的被动式:主要表示现在正在进行的动作,也可表示与谓语动作同时发生的动作:
如:Who is the woman being operated on? 正在动手术的女人是谁?
         I saw him being taken away by the police. 我看见他被警察带走。
:有时现在分词一般式的被动式所表示的动作也可发生在谓语动作之前(此时的现在分词通常用于表示原因,且多为状态动词):
如:Not having a car, he finds it difficult to get around. 由于没车,她感到行动很困难。
(2)现在分词完成式的被动式:主要表示发生在谓语动词之前且已经完成的动作。
如:The subject having been opened, he had to go on with it. 话题已经开始了,他不得不谈下去。
        Having been written inhaste, the book has many mistakes. 这书因写得仓促,所以错误不少。
比较:Being so ill, she can't go to school. 由于病得那么严重,她不能去上学。
            Having been ill for a long time, he needed time to recover. 由于病了很长时间,他需要一段恢复的时间。


一般过去时的概念

一般过去时表示过去某个时间里发生的动作或状态;过去习惯性、经常性的动作、行为;过去主语所具备的能力和性格。


一般过去时的用法:  

1、表示过去发生的动作或存在的状态,常与表示过去时间的副词如:yesterday,last week,two hours ago等连用。  
如:My family moved here five years ago. 我家五年前搬到了这里。  
        I was born in 1973. 我生于1973年。  
2、表示过去一段时间经常或反复发生的动作。这时可与频度副词如:often,usually,always等连用。  
如:He always worked in tonight those days. 那些日子他总是工作到深夜。  
        I often left on business in 1987. 1987年我经常出差。  
:表示“过去经常,而今不再”时,要用usedto.
如:I used to read newspaper after breakfast. 我过去经常早饭后看报纸。(意指现在已不是这样)   
The children often swam in this river. 孩子们过去经常在这条河里游泳。  
3、表示过去发生的一连串动作。  
如:He put down the heavy box, took out the keys, and opened the door. 他放下这沉重的箱子,掏出钥匙开了房门。  
注:过去发生的一连串动作,若用and,or,but等并列连词连接,则一律用过去式。  
如:They moved the chairs to the table, sat down and began to have  supper. 他们把椅子搬到桌边,坐下开始吃饭。  
4、在时间和条件状语从句中,用一般过去时表示过去将来的动作。  
如:He said that he would let me know as soon as he got the information. 他说他一得到消息就立即让我知道。         
Mary told me that she would stay at home if it rained. 玛丽告诉我如果下雨她就呆在家里。


一般过去时的特别用法

1、句型:It is time for sb. to do sth "到……时间了" "该……了"。
例如:It is time for you to go to bed.你该睡觉了。  
            It is time that sb.did sth. "时间已迟了" "早该……了"。
例如:It is time you went to bed. 你早该睡觉了。  
2、would(had)rather sb.did sth. 表示'宁愿某人做某事'。
例如:I'd rather you came tomorrow. 还是明天来吧。
3、wish, wonder, think, hope等用过去时,作试探性的询问、请求、建议等,而一般过去时表示的动作或状态都已成为过去,现已不复存在。
例如:I thought you might have some. 我以为你想要一些。
比较:Christine was an invalid all her life.(含义:她已不在人间。)  
            Christine has been an invalid all her life.(含义:她现在还活着)  
            Mrs. Darby lived in Kentucky for seven years.(含义:达比太太已不再住在肯塔基州。)      
            Mrs. Darby has lived in Kentucky for seven years.(含义:现在还住在肯塔基州,有可能指刚离去)
注意:用过去时表示现在,表示委婉语气。
1)动词want, hope, wonder, think, intend等。
例如:Did you want any thing else? 您还要些什么吗?   
            I wondered if you could help me. 能不能帮我一下。
2)情态动词could, would。
例如:Could you lend me your bike? 你的自行车,能借用一些吗?


状语从句的概念:

状语从句指句子用作状语时,起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。状语从句一般由连词(从属连词)引导,也可以由词组引起。从句位于句首或句中时通常用逗号与主句隔开,位于句尾时可以不用逗号隔开。


比较while/as/when:

1、as/when引导短暂性动作的动词例句:
如:Just as/Just when/When I stopped my car, a man came up to me.
2、当从句的动作发生于主句动作之前,只能用when引导这个从句,不可用as或while。
如:When you have finished your work, you may have a rest.
3、从句表示“随时间推移”连词能用as,不用when或while。
如:As the day went on, the weather got worse.

比较untill/till


两个连词意义相同,肯定形式表示的意思是“做某事直至某时”,动词必须是延续性的。否定形式表达的意思是“直至某时才做某事”,动词为延续性或非延续性都可以。
正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。
肯定句例句:I slept until midnight. 我一直睡到半夜时醒了。
                       Wait till I call you. 等着我叫你。
注意:在肯定句中可用before代替:Let's get in the wheat before the sunsets.
否定句例句:She didn't arrive until 6o'clock. 
                        I didn't manage to do it until you had explained how.
1、Until可用于句首,而till通常不用于句首。
例句:Until you told me, I had heard nothing of what happened.
2、Untilwhen疑问句中,until要放在句首。
例句:Until when are you staying? 你呆到什么时候?
注意:否定句可用另外两种句式表示。
1)Not until…在句首,主句用倒装。
例句:Not until the early years of the19th century did man know what heat is.
2)It is not until…that…


状语从句的用种类:

1、时间状语从句:
表示时间的状语从句可由when, as, while, whenever, after, before, till(until), since, once, as soon as(或the moment), by the time, no sooner…than, hardly(scarcely)… when, everytime等引导。   
e.g. When I came into the office, the teachers were having a meeting.   
       He started as soon as he received the news.   
       Once you see him, you will never forget him.   
       No sooner had I gone to bed than I went to sleep.   
2、原因状语从句:
原因状语从句是表示原因或理由的,引导这类从句的最常用的连词是because, since, as, nowthat(既然)等,for表示因果关系时(它引导的不是从句)为并列连词,语气不如because强。   e.g. He is disappointed because he didn't get the position.   
      As it is raining, I will not go out.   
      Now that you mention it, I do remember.   
3、地点状语从句:   
引导地点状语从句的连词是where和wherever等。   
e.g. Sit wherever you like.   
      Make a mark where you have a question.   
4、目的状语从句:   
引导目的状语从句最常用的词(组)是so, so that(从句谓语常有情态动词), in order that, in case(以防,以免)等。   
e.g. Speak clearly, so that they may understand you.   
      She has bought the book in order that she could follow the TV lessons.   
      He left early in case he should miss the train.   
5、结果状语从句:   
结果状语从句是表示事态结果的从句,通常主句是原因,从句是结果。由so that(从句谓语一般没有情态动词),so…that, such…that等引导。   
e.g. She was ill, so that she didn't attend the meeting.   
      He was so excited that he could not say a word.   
      She is such a good teacher that everyone admires her.   
6、条件状语从句:   
条件状语从句分真实性(有可能实现的事情)与非真实性(条件与事实相反或者在说话者看来不大可能实现的事情)条件句。
引导条件状语从句的词(组)主要有if, unless, so(as)long as, on condition that, so(as) far as, if only(=if)。
注意:条件从句中的if不能用whether替换。   
e.g. If he is not in the office, he must be out for lunch.   
      You may borrow the book so long as you keep it clean.   
      So far as I know(据我所知), he will be away for three months.   
      You can go swimming on condition that(=if) you don't go too far away from the river bank.   
      If he had come a few minutes earlier, he could have seen her.  
7、让步状语从句:   
让步状语从句可由although, though, as, even if(though), however, whatever, whether…or, no matter who(when, what,…)等引导。
注意:as引导的让步状语从句一般是倒装的。   
e.g. Though he is a child, he knows a lot.   
      Child a she is, he knows a lot.   
      Whatever(=No matter what) you say, I'll never change my mind.   
8、方式状语从句:   
方式状语从句常由as, as if(though), the way, rather than等引导。   
e.g.You must do the exercise as I show you.   
      He acted as if nothing had happened.   
9、比较状语从句:   
比较状语从句常用than, so(as)…as, the more…the more等引导。   
e.g. I have made a lot more mistakes than you have.   
      He smokes cigarettes as expensive as he can afford.   
      The busier he is, the happier he feels.


使用状语从句时要注意的几个问题:  

1、在时间和条件(有时也在方式、让步等)从句中,主句是一般将来时,从句通常用一般现在时表示将来。  
e.g. We'll go outing if it doesn't rain tomorrow.   
       I'll write to you as soon as I get to Shanghai.   
2、有些时间、地点、条件、方式或让步从句,如果从句的主语与主句主语一致(或虽不一致,是it),从句的谓语又包含动词be,就可省略从句中的“主语+be”部分。  
e.g. When(hewas) still a boy of ten, he had to work day and night.   
       If(you are) asked you may come in.   
       If(it is) necessary I'll explain to you again.   
3、注意区分不同从句:引导的是什么从句,不仅要根据连词,还要根据句子结构和句意来判别。以where为例,能引导多种从句。  
e.g. You are to find it where you left it.(地点状语从句)  
       Tell me the address where he lives.(定语从句,句中有先行词)  
       I don't know where he came from.(宾语从句)  
      Where he has gone is not known yet.(主语从句)  
       This place is where they once hid.(表语从句)
注意:表示“一…就…”的结构 hardly/scarcely…when/before/no sooner…than和as soon as都可以表示“一…就…”的意思。
例句:I had hardly/scarcely got home when it began to rain.
            I had no sooner got home than it began to rain.
           As soon as I got home, it began to rain.
注意:如果hardly/scarcely或nosooner置于句首,句子必须用倒装结构:
例句:Hardly/Scarcely had I got home when it began to rain.
            No sooner had I got home than it began to rain.


it的概念:

it可用作人称代词、指示代词、先行词及引导词等。


it 的用法:

1、it可指天气、温度、时间、距离等 。
如:It is cold today, isn't it?
2、用作人称代词,代替前文提到过的事物。
如:The dog is not  acold-blooded animals.  It doesn't need to hibernate.
3、为避免重复,it可用来代替前面说过的短语或句子。
如:I tried to persuade my father to give up smoking, but found it impossible. (it=to persuade my father to give up smoking)
4、代替指示代词this,that。
如:—What's this?
        —It's an album.
        —Whose new bike is that?
        —It's Mary's.
注:it与one,that的区别:
        it=the(this, that)+名词,特指并且代替前面所提到的某特定事物。
如:He's bought a new car, so he drives it everywhere to show ito ff.
        one=a+名词,one指前面提到的同类事物中的不同的另一个。
如:He needs a computer, but he can't afford one.
        that=the+名词,that指代的名词与前面的名词属于同一类,但不属同一个。
如:The population of China is larger than that of Japan.  that指代population,但其后有一个of短语作定语,以区别于the population of China。
:it与that的异同:
        it指同一事物,that指同类但并不是同一事物。
如:I like the climate of Kunming more than that of Beijing.
       The climate of Kunming is mild, and I like it.
5、It/This/That+be+the first(second, third...) time+that-clause 这个句型表示截止到说话时为止的某人的一种经历,关键是注意time前有序数词,主句是一般现在时is时,从句要用现在完成时;如果主句用一般过去时was时,则从句须相应地用过去完成时。
如:This is the first time(that) these Europeans have visited the Great Wall.
        It was the fifth time(that) I had paid a friendly visit to America.
6、在一些相对固定的词组中,没有特殊含义,经常不翻译。
如:He's never really made it as an actor. 作为演员,他从未获得过真正的成功。
        It is my turn. 轮到我了。


强调句中的it:

可以用来改变句子结构,使句子的某一成分得到强调:
1)强调句的基本句型it's/was+被强调成分+that/who+其他成分
原句:I told Jim the news in our office yesterday.
强调主语:It was I that/who told Jim the news in our office yesterday.
强调宾语:It was Jim that I told the news in our office yesterday.
            或:It was the news that I told Jim in our office yesterday.
强调地点状语:It was in our office that I told Jim the news yesterday.
强调时间状语:It was yesterday that I told Jim the news in our office.
2)强调句的一般疑问句型Is/Was+it+所强调部分+that/who...?
如:Was it you that told Jim the news in your office yesterday?
3)强调句的特殊疑问句型疑问词+is/was+it+that/who...?
如:Who was it that told Jim the news in your office yesterday?
【注】强调句与主语从句虽然在形式上很相似,即都含有it is(was)...that。但,区别在于:强调句去掉it is(was)…that之后,句子结构仍然完整,而主语从句却不能这样。
如:(It is)our hope(that) the two sides will work towards peace.
解析:去掉It is…that之后,句子是不成立的。由此得出该句不是强调句,而是一个简单的主语从句,it是形式主语,从句是真正的主语。


“it”的用法:

1、it 作形式主语:
it 在句中可作形式主语,而真正作主语的主语从句需要放在句子的末尾。主语从句后置常用以下几种结构:
1)It is/was+adj.+subject-clause可用于此句型的形容词有:
clear, certain, funny, good, impossible, likely, natural, obvious, possible, probable, strange, surprising, true, unusual, wonderful等。
如:It is obvious that going for sports will do a lot of good to your health.
2)It+be+adj./n.(forsb./ofsb.)+todosth. 该句型中的形容词通常表示事物的特点或特征的,如:
difficult, hard, easy, impossible, necessary, important等,此时用for;或表示人的性格特征或特点的,如:
nice, good, bad, kind, silly, foolish, wise, clever, careless, rude, brave, cruel, careful, grateful等,这时要用of 。
3)It is/was+名词词组+subject-clause可用于该结构的名词词组有:
a pity/duty, a good thing, no surprise, good news, an honor, a fact, a mystery, a shame, manners等。
 如:It's a pity that I didn't attend the party.
4)It is/was+V-ed+subject-clause可用于该结构的动词的过去分词有:
said, reported, thought, supposed, believed, hoped, expected, known, decided, announced, arranged等。
如:It is said that something had been done to end the pollution.
注:本句还可改写为:Something is said to have been done to end the pollution.
5)It+vi.+subject-clause可用于该结构的动词有:appear, seem, happen, occur等。
 如:It appeared to scientists that the stars had moved.
6)It doesn't matter(makes no difference,etc.) +连接代词或连接副词引起的从句作宾语。
如:It doesn't matter whether he'll join the army or not.
        It makes no difference where we have the conference.
7)一些固定句型:
It takes sb. some time to do sth.
如:It will take you two days to get there on foot. 
It costs sb. some money to do sth.
如:It costs 1,000 dollars to fly to America.
It is/was no use(useless) doing(做什么是没有用处的)
如:It's no use arguing with him.
It is/was no good doing(做什么是没有好处的)
8)以下句型结构中需要用虚拟语气
① It is/was important(necessary, strange) that...;
     It is/was ordered(required, suggested, proposed) that...;
     It is/was a pity(a shame) that...表示遗憾等感情的句子中,主语从句要用“should+动词原形”,should可以省略。
如:It's necessary that he(should) be operated on at once.
② It is (high)time that...结构中用should+动词原形(should不能省略)或动词过去式。
如:It is high time that you should make(made) full use of your time to go over your lessons.

2、it作形式宾语
1)动词consider(feel, find, think等)+it+形容词(名词)+不定式(动词-ing形式,从句)。
 如:She thinks it no use telling me.
2)主语+appreciate(enjoy,like,love,hate)+it+if(when)...结构
如:We would appreciate it if you could come to help us.
3)dependon, relyon, see to(负责/设法做到), takeforgranted(习以为常)等短语后跟that从句时,要以it作形式宾语。
如:We're depending on it that he will finish the job by Friday.


“it ”引起的几个易混淆的时间句型:

1)It be+时间+since-clause 这个句型表示从since从句谓语动作发生以后到现在或过去所经过的一段时间,意为“自从…以来已多久了”,主句多用一般现在时,从句用一般过去时,如果表示过去的情况,主句一般用过去时,从句用过去完成时,或主句用过去完成时,从句用一般过去时。
:since引导时间状语从句时,从句若使用终止性动词,则表示该时间是主句时间段的终点(时间从现在算起);若从句使用延续性动词,则表示该动作状态的结束(时间从过去算起)。
如:It's five years since they got married. 他们结婚已经5年了。 
        It's five years since they were married. 他们离婚已经5年了。
        It's ten years since his father was a worker. 他父亲不当工人已经10年了。
        I haven't seen him since we were boys together. 我们长大以后再没有见过面。 
2)It be+时间+before-clause 这个句型中的时间一般为表示一段时间的词语(如:long years, months, weeks, days, hours, minutes),主句中的谓语动词用肯定式,意为“过多长时间才…”。主句的谓语动词是否定式时,意为“没过多长时间就…”。主句的时态可用过去时was或将来时willbe;用was时,before从句的动词用一般过去时;用willbe时,before从句常用一般现在时。 如:It was not long before she learned those poems by heart. 她没过多久就背会了那些诗。
        It was long before the police arrived. 过了很久警察才来。
        It will be hours before he makes a decision. 要过好几个小时他才会作出决定。
        It will not be hours before we meet again. 要不了几个小时我们还会再见面的
3)It be+时间+when-clause 这个句型中,it指时间,而且表示时间的词语前没有介词(时间一般是具体时间)。主句和从句中的谓语动词在时态上是一致的,主句是willbe,when从句用一般现在时代替将来时。
如:It was already 8 o'clock when we got home.
        It will be late afternoon when they get there. 
4)It be+时间+that-clause 这个句型是个强调句型。
如:It was at 5o'clock that he practiced playing the violin in the morning. (原句是:He practiced playing the violin at 5o'clock in the morning.)
比较:It was 5o'clock when he started in the morning.(5o'clock前没有介词,这个是定语从句)
5)It be+time+that-clause 这个句型属虚拟语气结构,不管主句中用的是is或was,that从句都须用动词的过去式或should+动词原形(但不及物动词通常用过去式),在time之前有时可以加上high 或about 以加强语气。
如:It is high time(that) he wrote a letter to his girl friend.
        It is time(that) we made people's life a little easier.= It is time that we should make people's life a little easier.