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初中三年级英语

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  • 句型转换
    句型转换。
    1. I don't know how I can get to the zoo. (改为简单句)
    I don't know______to the zoo.
    2. The doctor asked her,” Are you feeling better?"  (改为宾语从句)
    The doctor asked her _                                  feeling better.
    3. The Smiths said they would visit Beijing next year,______?
    4. I think. He isn't a bad boy.  (合并为一句)
    I______ think that he______a bad boy.
    5. How can I search the Internet?(合并为一句)
    Could you tell me__________________search the Internet?
    Could you tell me ____________search the Internet?
    本题信息:2012年同步题英语句型转换难度一般 来源:孔建伟
  • 本题答案
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本试题 “句型转换。1. I don't know how I can get to the zoo. (改为简单句)I don't know______to the zoo.2. The doctor asked her,” Are you feeling better?" (改...” 主要考查您对

不定式

并列连词

反意疑问句

宾语从句

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。
  • 不定式
  • 并列连词
  • 反意疑问句
  • 宾语从句
动词不定式:
指由to加上动词原形(而且只能是动词原形)所构成的一种非限定性动词,但在有些情况下to可以省略。
动词不定式在语法功能上可作主语、宾语、宾语补足语、表语、定语和状语。
动词不定式可以作以上各种成分,但它毕竟是动词,所以有动词的属性。
动词不定式及其短语还可以有自己的宾语、状语,虽然动词不定式在语法上没有表面上的直接主语,但它表达的意义是动作,这一动作一定由使动者发出。
这一使动者我们称之为逻辑主语,其形式如下:
时态 主动形式  被动形式 
一般式 (not) to do (not) to be done
完成式 (not) to have done (not) to have been done
进行式 (not) to be doing  
完成进行式 (not) to have been doing  

不定式的用法:
1、不定式作主语
例如:To remember this is very important.
注意:为了避免头重脚轻,在许多情况下,通常都将作主语的不定式置于句子后部,而在句首主语位置使用形式主语it。
例如:It is very important to remember this.
2、不定式作表语
例如:He seems to be ill.
注意:不定式作表语主要有三种情况,一是用于seem, appear, prove等系动词之后的不 定式(尤其是to be),
二是像My job is to sweep the floor. 这样的主语与表语“等价”的情形,
三是表示想法、约定、义务、命令、可能性、命运等,如: 
You are to come when I call.
3、不定式作宾语
例如:I can not afford to buy a car.
注意:
①不定式不仅用作动词的宾语,还可用作个别介词(but, except)的宾语。
例如:I had no choice but to wait.
②当作宾语的不定式后跟有宾语补足语时,通常要用形式宾语it代替不定式,并将真正的宾语不定式置于宾语补足语之后
例如:I find it difficult to learn Japanese well.
4、不定式作宾语补足语
例如:Who taught you to drive?
5、不定式作定语
例如:I have a question to ask you.
注意:有的名词(如way, chance, right等)后用作不定式可换成of doing sth.
如:It is the best way to do (of doing) it.
但是以下名词后接不定式作定语时通常不能换成of doing sth.
attempt  courage  decision  effort  fortune  failure  invitation  wish
6、不定式作状语
例如:I went to France to learn French.
并列连词
主要是用来表示并列关系、选择关系、因果推理关系等。也可用来连接平行的词,词组或分句。

并列连词表示关系及代表实例:
1.表示并列关系
表示并列关系的连词主要含有“和”、“补充”、“增加”等意思。用来表达并列关系的连词有如下几个:
and 和 both...and...二者都
either...or...或者...或者...
neither...nor...既不...也不...
as well as 也、连同
not only...but (also)... 不但...而且...
e.g.
I used to live in Paris and London.
我过去住在伦敦和巴黎。
Both Jane and Jim are interested in pop music.
詹妮和吉姆对流行音乐都很感兴趣。
She is not only kind but also honest.
她不但和蔼而且诚实。
Bob as well as his parents is going on holiday this summer.
鲍勃和他的父母今年夏天要去度假。

2.表示转折关系
常用来表示转折关系的并列连词有如下几个:
but 但是
yet 然而
still 仍然
while 然而
while 然而、偏偏
e.g.
The winter in Beijing is very cold while that of Kunming is warm.
北京的冬天很冷,然而昆明的冬天却很温暖。
I explained twice, still he counldn't understand.
我解释了两遍,然而他却还不懂。

3.表示选择关系
表示选择关系的并列连词:
or 或者
or else 否则
otherwise 否则
neither...nor... 既不...也不...
either...or... 或者...或者...
e.g.
Would you like leave or would you like to stay?
你是想走还是想留?
You can come either on Saturday or on Sunday.
你可以星期六来也可以星期天来。
Neither you nor I nor anyone else believes such things.
不管你我或者其他任何人都不会相信这件事。

4.表示因果推理关系
表示因果关系的并列连词主要有so,for,then,therefore 等。
e.g.
The air here is polluted, so the crops are dying.
这里的空气受到了污染,所以庄稼快死了。
The leaves of the trees are falling, for it's already autumn.
树叶在落下,因为秋天已经到来了。


并列连词注意事项:
并列连词for引导的分句只能放在句尾,前面用逗号隔开,表示补充说明的微弱理由,只是为前面的内容提供判断的理由,有时译为并列的某种形式。
这与because不同,because引导的是一种明确的因果关系,解释原因,常可回答why的提问。
几个特殊并列连词用法:
一、表示并列关系的and,or,well,as,not only...but also... 等连词也有比较活跃的用法。
and 作为并列连词有多重含义,除了可以表示并列关系外,还可以表示顺承、目的、条件、反复等关系。
e.g:He went to market and bought some vegetables.(表示顺承,动作的先后发生)
他到市场买了一些蔬菜。
Come and help me out.(表示目的)
过来帮我一下。
Be careful and you'll make fewer mistakes.(表示条件)
如果仔细,你所犯的错就少。

二、or 与 either...or...
or表示为“否则”的话,前句一般是祈使句,后句用一般将来时。
在表示选择关系时or 与 either...or... 用法相同,但 either...or...更具强调性。
在多个对象进行选择时,可以用A or B or C... , either A or B or C... , neither A or B or C... 。
e.g:Either Jim or Jake or Jeff knows about this.

三、as well as 与not only... but also...
名词+as well as+名词作主语时,强调前面的名词,谓语动词要根据前面的名词而定。
not only...but also...连接名词作主语时,其强调在后者,谓语动词要根据后面的名词而定。
e.g:China as well as many other countries loves peace.
中国与世界上的其他许多国家一样热爱和平。
Not only Bill but also his parents want to go traveling by bike.
不仅比尔而且他的父母都想骑自行车去旅游。
注:当or,neither...nor...,either...or 等连接主语时,谓语动词由or或nor后面的部分而定。
并列连词表示关系:

种类

用法 

举例 

并列连词

表示转折关系

but, yet等

表示因果关系

For, so等

表示并列关系

And, or, either…or,
neither…nor, not only..
but also, as well as等


反义疑问句:
表示提问人的看法,没有把握,需要对方证实。
反意疑问句由两部分组成:前一部分是一个陈述句,后一部分是一个简短的疑问句,两部分的人称时态应保持一致。
1. 陈述部分肯定式+疑问部分否定式可记为前肯后否。 
2. 陈述部分否定式+疑问部分肯定式可记为前否后肯。
例如:This pencil is red, isn’t it? Yes, it is. / No, it isn’t. 
               This pencil isn’t red, is it? Yes, it is. / No, it isn’t.
速记:
前肯后否,前否后肯,前be后be,前无be后加助,时态一致。

反意疑问句的回答
前肯后否,前否后肯,根据事实从后往前翻译。如:
(1)They work hard,don’t they?他们努力工作,不是吗?
Yes, they do.对,他们工作努力。/No, they don't.不,他们工作不努力
(2)They don’t work hard, do they? 他们不太努力工作,是吗?
Yes, they do. 不,他们工作努力。/No, they don't. 是的, 他们工作不努力

否定反义疑问句的回答
当陈述部分为肯定式,反义疑问句为否定式时,其回答一般不会造成困难,一般只需照情况回答即可:
"It’s new, isn’t it?" "Yes, it is." “是新的,不是吗?”“是,是新的。”
"He wants to go, doesn’t he?" "No, he doesn’t." “他想去,不是吗?”“不,他不想去。”
此时,"Yes"即是,对前面"It's new."的肯定。

回答反义疑问句的原则
回答反意疑问句通常应根据实际情况来确定,
如有人问你You are asleep, aren’t you? 你应回答No, I’m not. 因为既然你能回答,肯定你还没有asleep。
但如果别人问你 You aren’t asleep, are you?(你还没有睡着,对吗),你也只能回答No, I’m not.(是的,还没有睡着),而不能回答为Yes, I’m not. 也不能回答成 Yes, I am.
“It is a beautiful flower,isn't it?” “It isn't a beautiful flower,is it?”
上述两句句子的回答肯定均为“Yes,it is."否定为“No,it isn't."
由上述例子可知,反义疑问句回答与句子本身所包含的中文肯定与否的含义并无太大关联,只需注意事实,肯定即用yes,否定用no,无需考虑句子原本是前否后肯或是前肯后否。

口诀:
反意疑问并不难,陈述疑问句中含。
前后肯否恰相反,否定词缀不能算。
主谓时态要一致,特殊情况记心田。
实际情况来回答,再把yes和no拣。
综上所述,反义疑问句回答就是按实际情况回答。
对反意疑问句的回答,无论问题的提法如何,如果事实是肯定的,就用yes,事实是否定的,就要用no。
要特别注意陈述句部分是否定结构,反意疑问句部分用肯定式提问时,回答yes或no与汉语正好相反。这种省略回答的yes要译成“不”,no要译成“是”。
例:
—He likes playing football, doesn’t he? 他喜欢踢足球,不是吗?
—Yes, he does. / No, he doesn’t. 是的。/ 不是。
—His sister didn’t attend the meeting, did she? 他妹妹没有参加会议,是吗?
—Yes, she did. / No, she didn’t. 不,她参加了。/ 是的,她没参加。


快速记忆表:
陈述部分的谓语   疑问部分
I/主语   aren't I / are I
no,nothing,nobody,never,few, seldom, hardly,rarely, little等否定含义的词   肯定含义
含有un-,in-.dis-,im-等否定意义的前缀构成的词语时,视为肯定含义   否定含义
ought to(肯定的)   shouldn't/ oughtn't +主语
have to+v.(had to+v.)   don't +主语(didn't +主语)
used to+v.   didn't +主语或 usedn't +主语
had better + v.   hadn't you
would rather + v.   wouldn't +主语
you'd like to + v.   wouldn't +主语
must   根据实际情况而定
感叹句   be +主语
指示代词或不定代词everything,that,nothing,this   主语用it
并列复合句   谓语根据邻近从句的谓语而定
定语从句,宾语从句主从复合句   根据主句的谓语而定
think,believe,expect,suppose,imagine等引导   与宾语从句相对应的从句
everybody,anyone,somebody,nobody,no one   复数they, 单数he
情态动词dare或need   need/needn't (dare/daren't ) +主语
dare, need 为实义动词   do/don't +主语
省去主语的祈使句   will/won't you?
Let's 开头的祈使句   Shall we?
Let us 开头的祈使句   Will you?
there be   相应的谓语动词+there(省略主语代词)
否定前缀不能视为否定词   仍用否定形式.
反意疑问句19条:
1) 陈述部分的主语是I,疑问部分要用 aren't I.
I'm as tall as your sister,aren't I?
2) 陈述部分的谓语是wish,疑问部分要用may +主语。
I wish to have a word with you, may I?
3) 陈述部分用 no, nothing, nobody, never, few, seldom, hardly, rarely, little等否定含义的词时,疑问部分用肯定含义。
The Swede made no answer, did he / she?
Some plants never blown (开花), do they ?
4) 含有ought to 的反意疑问句,陈述部分是肯定的,疑问部分用shouldn't / oughtn't +主语。
He ought to know what to do, oughtn't he? / shouldn't he?
5) 陈述部分有have to +v. (had to + v.),疑问部分常用don't +主语(didn't +主语)。
We have to get there at eight tomorrow, don't we?
6) 陈述部分的谓语是used to 时,疑问部分用didn't +主语或 usedn't +主语。
He used to take pictures there, didn't he? / usedn't he?
7) 陈述部分有had better + v. 疑问句部分用hadn't you?
You'd better read it by yourself, hadn't you?
8) 陈述部分有would rather +v.,疑问部分多用 wouldn't +主语。
He would rather read it ten times than recite it, wouldn't he?
9) 陈述部分有You'd like to +v. 疑问部分用wouldn't +主语。
You'd like to go with me, wouldn't you?
10) 陈述部分有must 的疑问句,疑问部分根据实际情况而定。
He must be a doctor, isn't he?
You must have studied English for three years, haven't you? / didn't you?
He must have finished it yesterday, didn't he?
11) 感叹句中,疑问部分用用否定的助动词加sb/sth?如:
1)What a fine day it is today!
What a fine day it is today,isn“t it?
2)How fast he runs!
How fast he runs,doesn”t he?
3)What a long time we have been waiting!
What a long time we have been waiting ,haven“t we?
12) 陈述部分由neither… nor, either… or 连接的并列主语时,疑问部分根据其实际逻辑意义而定。
Neither you nor I am engineer, are we?
13) 陈述部分主语是指示代词或不定代词everything, that, nothing, this, 疑问部分主语用it。
Everything is ready, isn't it?
14)陈述部分为主语从句或并列复合句,疑问部分有三种情况:
a. 并列复合句疑问部分,谓语动词根据邻近从句的谓语而定。
Mr. Smith had been to Beijing for several times, he should have been in China now, shouldn't he?
b. 带有定语从句,宾语从句的主从复合句,疑问部分谓语根据主句的谓语而定:
He is not the man who gave us a talk, is he?
He said he wanted to visit Japan, didn't he?
c. 上述部分主句谓语是think, believe, expect, suppose, imagine等引导的定语从句,疑问部分与宾语从句相对应构成反意疑问句。
I don't think he is bright, is he?
We believe she can do it better, can't she?
15) 陈述部分主语是不定代词everybody, anyone, somebody, nobody, no one等,疑问部分常用复数they,有时也用单数he。
Everyone knows the answer, don't they? (does he?)
Nobody knows about it, do they? (does he?)
16) 带情态动词dare或need的反意疑问句,疑问部分常用 need (dare ) +主语。
We need not do it again, need we ?
He dare not say so, dare you?
当dare, need 为实义动词时,疑问部分用助动词do + 主语。
She doesn't dare to go home alone, does she?
17) 省去主语的祈使句的反意疑问句,疑问部分用will you。
Don't do that again, will you?
Go with me, will you / won't you ?
注意: Let's 开头的祈使句,后用shall we?
Let us 开头的祈使句,后用will you?
Let's go and listen to the music, shall we?
Let us wait for you in the reading-room, will you ?
18) 陈述部分是"there be"结构的,疑问部分用there省略主语代词。
There is something wrong with your watch, isn't there?
There will not be any trouble, will there?
19) 否定前缀不能视为否定词,其反意疑问句仍用否定形式。
It is impossible, isn't it?
He is not unkind to his classmates, is he?
有些动词如:cost hurt hit put 等,它们的过去时与原型相同,在肯定句中一定要先弄清楚它们是什么时态.
英语18种特殊的反意疑问句:
1.祈使句。祈使句后一般加上will you或won't you构成反意疑问句,用will you 多表
示“请求”,用won't you 多表示提醒对方注意。例如:    
Look at the blackboard, will you/ won't you?看黑板,好吗?   
Let 引导的祈使句有两种情况:   
1) Let's...后的反意疑问句用shall we或shan't we。例如:   
Let's go home, shall we/ shan't we? 回家吧,好吗?    
还可以用may I来表示征求对方的同意或许可。   
2) Let us/me...后的反意疑问句用will you或won't you。例如:    
Let me have a try, will you/won't you? 让我试一试,行吗?   
2. 感叹句。感叹句后加反意疑问句时,其反意疑问句需用be的一般现在时态的否定形式。 例如:   
What fine weather, isn't it? 多好的天气啊,是吧?    
3. 当陈述部分谓语动词是need, dare, used to,且这些词被用作实义动词时,其反意疑问 句需用do的适当形式。例如:   
He needs help, doesn't he? 他需要帮助,是吗?    
4. 陈述部分主、谓语是I am...时,反意疑问句用aren't I 或am't I ,而不是am not I (可 用a m I not)。例如:   
I'm working now, am't I? 我在工作,是吗?   
5. 陈述部分的主语是everything, nothing, anything或something 时,反意疑问句的主语应用代词it。例如:    
Something is wrong with my radio, isn't it? 我的收音机出毛病了,是吧?   
6. 陈述部分的主语是 everybody, everyone, anybody, anyone, somebody, someone, nobody, no one, none, neither 时, 其反意疑问句的主语需用复数代词they。 例如:   
Everyone is here, aren't they? 大家都到了,是吗?   
No one knows about it, do they? 没有人知道这件事,对吗?   
7. 陈述部分的主语是指示代词this或that时,反意疑问句的主语用it,当陈述部分的主语是指示代词these或those时,其反意疑问句的主语用they。 例如:   
This is a plane, isn't it? 这是一架飞机,是吗?   
These are grapes,aren't they? 这些是葡萄,是吗?   
8. 陈述部分的主语是不定代词one时,反意疑问句的主语可以用one,也可用you(美式英语用he)。例如:   
One should be ready to help others, shouldn't one? 每个人都应该乐于助人,是吧?   
9. 当陈述部分含有以下这些含有否定意义的词时:few, little, seldom,hardly, never, not,  no, no one, nobody, nothing, none, neither等,其反意疑问句需用肯定结构。 例如:    
He is never late for school, is he? 他上学从不迟到,是吗?   
10. 当陈述部分所含的否定词是通过加前缀或后缀构成的,其后的反意疑问句依然用否定结构。例如:   
   It is unfair, isn't it? 这不公平,是吧?   
11.含有否定含义的词在陈述部分作动词的宾语时,其反意疑问句用肯定结构,也可以用否定结构。例如:   
You got nothing from him, did you? 你从他那儿什么也没得到,是吗?   
12. 当陈述部分主语是从句、不定式(短语)、动词-ing形式时,反意疑问句的主语应该用it。  例如:   
What you need is more important, isn't it?你需要的东西更重要,是吧?   
13. 当陈述部分含I think (believe, suppose...)that... 结构时,其反意疑问句须与从句的主、谓语保持一致,注意主句的主语必须是第一人称。例如:   
I don't think he will come, will he? 我认为他不会来,对吗?   
14.have(has)不是表示“有”的意思,并在句中做谓语时,其反意疑问句的助动词要用do, does, did。例如:   
They had a meeting just now,didn't they? 他们刚才开了个会,是吗?   
15. 陈述部分有have to 时,其反意疑问句要用助动词的否定形式。例如:   
You have to water the vegetables every day, don't you?你每天都要浇菜,对吧?   
16. 陈述部分是there be句型时,其反意疑问句中要用there。例如:   
There was a hospital here, wasn't there? 过去这儿有家医院,是吗?   
17. 陈述部分有had better时,反意疑问句中要用hadn't。 例如:   
We had better go to school at once, hadn't we? 我们现在最好马上去上学,好吗?
18. 当陈述部分含有情态动词must时,我们便要分析一下must的含义。如果must 作“一定;要;必须”讲,反意疑问句须用mustn't或needn't;
而当must作推测意义“一定 是;必定”讲时,反意疑问句则需根据must后的动词原形选用相应的形式。例如:    
He must work hard at physics, mustn't he? 他必须努力学物理,是吧?   
Tom must be at home,isn't he? 汤姆一定在家,是吧?
宾语从句:
在句子中起宾语作用的从句叫做宾语从句。
宾语从句分为三类:动词的宾语从句,介词的宾语从句和形容词的宾语从句。
宾语从句连接代词主要有:
who, whom ,whose ,what ,whoever ,whomever ,whosever, whatever, whichever 等。

宾语从句的特点:
1.宾语从句可以作及物动词、介词及形容词的宾语。
2.宾语从句的语序一律用陈述句语序。
3.连接词that引导宾语从句在句中无词义,不充当句子成份,多数情况下可以省略。
4.whether 和 if 都可引导宾语从句,但 whether后可紧跟or not;whether从句可作介词的宾语。
5.如果从句太长,可以用形式宾语it.

宾语从句的时态:
1.主句是一般现在时,从句根据实际情况使用任何时态。
例句:The headmaster hopes everything goes well.
2.主句是过去时态,从句须用过去时态的某种形式。
例句:She was sorry that she hadn’t finished her work on time.
3.当宾语从句表示的是一个客观真理或者事实时,即使主句是过去时,从句也用一般现在时态。
例句:The teacher told his class that light travels faster than sound.
4. 如果从句的动作发生在主句之前,则从句要用过去完成时态。 

宾语从句的语序:
A. 宾语从句必须用陈述语序。   
False: He is wondering when can he finish this difficult job.   
Right: He is wondering when he can finish this difficult job.
B. 有时候可以用it 作形式宾语,而把真正的宾语从句放在后面。    
Bad: I thought that he could finish this job in just two hours impossible.   
Good: I thought it impossible that he could finish this job in just two hours.  
C. 带有宾语从句的复合句的否定形式一般是否定主句。
Bad: I think he doesn’t like the English teacher.   
Good: I don’t think he likes the English teacher. 
D.  主句一般过去时态,从句也要用过去时态。
False: He wanted to know why he is crying in the corner.   
Right: He wanted to know why he was crying in the corner

宾语从句的否定转移:
主句的谓语动词是think,believe,imagine,suppose,consider,espect,fancy,guess等。
并且主句的主语是第一人称而且为一般现在时,从句的否定词一般要转移到主句上来,其反义疑问句一般与宾语从句一致。
I don’t think he will come to my party.而不能说成I think he won’t come to my party.
我认为他不会来我的舞会.
I don’t believe that man is killed by Jim,is he?
我认为那个人不是Jim所杀的,是不是?
如果宾语从句中有某个含有否定意义的形容词或副词,其反义疑问句要用肯定形式。
We find that he never listens to the teacher carefully,does he?
我们发现他从来不仔细听老师讲课,是不是?


宾语从句中引导词的用法比较
在复合句中作主句的宾语,引导词有:
连词:that (that 常可省略),whether, if
代词:who, whose, what ,which
副词:when ,where, how, why 等。

(一)that引导的宾语从句(在非正式场合that可以省略)
1.可跟that从句做宾语的动词有:
say, think, insist, wish, hope, demand, imagine, wonder, know, suppose, see, believe, agree, admit, deny, expect, explain, order, command, feel, dream, suggest, hear, mean, notice, prefer, request, require, propose, declare, report等。
例句:The boy believes that he will travel through space to other planets.
注意事项:当主句谓语动词是 think, believe, suppose, expect 等词,而宾语从句的意思是否定时,常把否定转移至主句表示。
例句:I don’t think it is right for him to treat you like that.

2.在以下情况中that不能省略
a.当句中的动词后接多于两个由that引导的宾语从句时,第一个that可省,但后面的that不可省。
例句:He said (that) you were too young to understand the matter and that he was asked not to tell you.
b.当主句的谓语动词与that宾语从句之间有插入语时,that一般不可省。
例句:Just then I noticed, for the first time, that our master was wearing his fine green coat and his black silk cap.
c.当that从句是双宾语中的直接宾语时,that不可省。
例句:I can’t tell him that his mother died.
d.注:许多带复合宾语的句子,that引导的宾语从句经常移到句子后部,而用it作形式宾语。
例句:I find it necessary that we should do the homework on time.

(二)由whether,if 引导的宾语从句
1.由whether(if)引导的宾语从句,实际上是一般疑问句演变而来的。意思是“是否”。宾语从句要用陈述句语序。
一般说来,在宾语从句中whether与if可以互换使用,但在特殊情况下if与whether是不能互换的。
例句:I wonder whether(if) they will come to our party.

2.只能用whether,不能用if引导的宾语从句
a.在带to的不定式前
例句:We decided whether to walk there.
b.在介词的后面
例句:I’m thinking of whether we should go to see the film.
c.在动词后面的宾语从句时
例句:We discussed whether we had a sports meeting next week
d.直接与or not连用时
例句:I can’t say whether or not thet can come on time.

3.只能用if不能用whether引导的宾语从句
a.if引导条件状语从句,意为“如果”
例句:The students will go on a picnic if it is sunny.
b.if引导否定概念的宾语从句时
例句:He asked if I didn’t come to school yesterday.
c.引导状语从句even if(即使)和as if(好象)时
例句:He talks as if he has known all about it.

if,whether在宾语从句中的区别
a.if和whether在作“是否”解时,引导宾语从句常放在动词know,ask,care,wonder,find out等之后,介词后一般不用if
b.少数动词,如:leave,put,discuss,doubt后的宾语从句常用whether. 
c. whether后可以加or not,但是if不可以.
d.在不定式前只能用whether.
(如:I can’t decide whether to stay. 我不能决定是否留下。)
e.避免歧异时,我们常用whether而不用if.

(三)连接代词和连接副词引导的宾语从句
这样的宾语从句实际上是由特殊疑问句变化而来的,宾语从句要用陈述句语序。
用于这种结构的动词常常是:see, say, tell, ask, answer, know, decide, show, find out, imagine, suggest, doubt, wonder, discover, understand, inform, advise等。
1.英语中的连接代词有:who,whom,whose,which,what,在句中担任主语、宾语、定语或者表语。
例句:Can you tell me whom you are waiting for?
2.英语中的连接副词有:when,where,why,how,在句中担任状语的成分。
例句:None of us knows where these new parts can be bought.


简化宾语从句常用六法:
方法一:
当主句谓语动词是hope, decide, wish, choose, agree, promise等,
且宾语从句的主语与主句主语一致时,宾语从句可简化为不定式结构。
例如:
Li Ming hopes he will be back very soon.
→Li Ming hopes to be back very soon.
We decided that we would help him.
→We decided to help him.

方法二:当主句谓语动词是know, learn, remember, forget, tell等动词,
且主句主语与从句主语一致时,宾语从句可简化为“疑问词+不定式”结构。例如:
She has forgotten how she can open the window.
→She has forgotten how to open the window.
注:当主句谓语动词是tell, ask, show, teach等动词,
且后带双宾语,从句主语和间接宾语一致时,宾语从句可简化为“疑问词+不定式”结构。例如:
Could you tell me how I can get to the station?
→Could you tell me how to get to the station?

方法三:当主句的谓语动词是order(命令),require(需要)等时,
如果主句和从句的主语不一致,宾语从句可简化为“名词(代词)+不定式”结构。例如:
The headmaster ordered that we should start at once.
→ The headmaster ordered us to start at once.

方法四:某些动词后的宾语从句,可以用介词加动名词(短语)等其他形式简化。例如:
He insisted that he should go with us.
→He insisted on going with us.
The poor boy doesn’t know when and where he was born.
→The poor boy doesn’t know the time and the place of his birth.

方法五:某些动词后面的宾语从句可转化为“宾语+V-ing形式(作宾语补足语)”结构。例如:
Liu Ping found that there was a wallet lying on the ground.
→ Liu Ping found a wallet lying on the ground.

方法六:动词seem后的宾语从句,也可以用不定式(短语)来简化,但句型需要进行适当的变化。例如:
It seemed that the boys were going to win.
→The boys seemed to win.
除上述方法外,还有一些特殊句式的转化。例如:
I found that it was difficult to learn English well.
→I found it difficult to learn English well.
Soon we found that the ground was covered with thick snow.
→Soon we found the ground covered with thick snow.
They found that the box was very heavy.
→They found the box very heavy