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11.        宾语从句中的虚拟语气
1）        宾语从句用动词原形表示虚拟语气（省略了should）
        表建议
advocate/advise/move/recommend that ... do ...
sb. suggest/propose that ... do ...
The doctor recommended that I give up smoking.
        表命令
order/decree/mandate/command/demand that ... do ...
I did not receive the order that you leave here at once.
        表要求
request/require/insist that ... do ...
sth. require of sb. that ... do ...
2）        不使用虚拟语气的宾语从句
allow that ...；rule that ...；sth. propose that ...；sth. suggest that ...
12.        虚拟语气的强弱
要保持原语气的强弱，不能随意改变。
only if和if不能替换；however much和however不能替换；should和if不能替换；be not unlike和be like不能替换；if和on condition that不能替换；any n.和n.不能替换；just like和like不能替换。
13.        情态动词的功能
    情态动词（can/could，may/might，shall/should，will/would，must，need，ought to）用来帮助主动词构成复合谓语，即情态动词+主动词=复合谓语。情态动词本身能够表示说话者对所述动作或状态的态度和看法。
1）        “推测性”和“非推测性”用法。must表示推测时没有否定结构
情态动词        非推测性用法        推测性用法
can / could        表示能力、许可        表示可能
may / might        表示许可        表示可能
will / would        表示意志、意愿        表示推测
should / ought to        表示义务、必须        表示必然
must        表示义务、必须        表示必然
2）        情态动词 + 动词的完成时，表示推测
3）        would，should，could和might可用在非真实条件句中表示假象的可能，以至非事实
4）        口语中，would、could、will和can表示“请求”意义，常用于疑问句，委婉口气依次减弱，GMAT中不考这一内容，只考can和could在时态上的区别
5）        must，need，ought to和should，表示“必然”意义，强度逐渐减弱。其中need可做实义动词使用
6）        shall，should，will可以表示“纯粹未来”
7）        may可以表示“让步”意义，常见于whatever为主语的让步从句中，文体较正式
14.        情态动词可能程度的强弱顺序
由强到弱：must（=will have to），would，should，can，could，may，might。除了may和might可以替换外，情态动词都不能互相替换。
15.        “能力”和“可能性”的区别
    根据生活事理或上下文逻辑关系判定是“能力”还是“可能性”。
1）        can/could和cannot/could not强调“可能性”
2）        be able to / be unable to强调“能力”，表示特定的过去、现在或者未来的能力，或经过某种努力而成功获得的能力
3）        will be able to表示将来“能力”或将来“可能性”
16.        情态动词的省略和添加
1）        原句有情态动词时，一般不省略
2）        当使用情态动词导致前后文语义重复时，情态动词必须省去
the possibility that ... might do => the possibility that ... do
3）        情态动词不能随意改变或添加，除非上下文逻辑关系有要求
17.        so that从句中的情态动词
so that状语从句中，出现情态动词，表示目的，没有出现情态动词，表示结果。

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四、分词和不定式
1.        -ing分词的形式
        及物动词        不及物动词
        主动        被动        主动
现在        doing        being done        vi. + ing
完成        having done        having been done        having vi. + ing
2.        –ing分词的功能
1）        作主语：doing ... is / was / did / does ...
2）        作补语：find / keep / have / make + 名词短语 + -ing分词
3）        作宾语：-ing分词既可以做动词宾语，也可以做介词宾语
4）        作定语：-ing分词做定语时，它所修饰的词一般是分词所表示的行为或状态的主体，从逻辑上看似乎是一种主语和谓语的关系
5）        作状语：-ing分词作状语一般放在句首或者句尾
3.        -ed分词的功能
1）        作补语：find / keep / have / make + 名词短语 + ed分词
2）        作定语：-ed分词作定语时，被修饰的词是分词所表示行为的承受者，从逻辑上看，修饰语和被修饰语之间似乎是一种行为与客体之间的关系
3）        作状语：-ed分词作状语时位于主谓结构之外
4.        分词逻辑主语的判断
1）        分词短语在句首作状语时，逻辑主语等于句子主语
2）        -ing短语在句尾
        表示伴随动作、状态、功能，与句子的谓语动作同时发生，逻辑主语等于句子主语
        表伴随结果，整个句子是原因，无逻辑主语，可在分词前加thus、thereby、in effect等，也可不加
3）        -ed短语在句尾，一般优先就近作定语，修饰名词
4）        介词或介词短语 + -ing分词
in addition to / in / by / without / besides + doing ...，句子
        在句首，逻辑主语等于句子主语
        在句尾，可能是句子主语，也可能不是
5.        分词短语的并列
    -ing分词短语和-ed分词短语可以并列，作定语修饰名词
6.        分词的否定形式
    not doing ... / without doing ... / not –ed ... / never –ed ...
7.        -ing分词的完成时态
    -ing分词的完成时态不能充当名词的定语，必须转换为定语从句
n. + having done ... / having been done ... => n. that ...
8.        定语从句与分词短语的区别
1）        定语从句强调具体的时间、具体的行为，以及动作的一次性；分词短语强调笼统的、不确定的时间，抽象的、客观的、重复性的、多次性的行为
2）        分词短语比定语从句简洁：两者都可以接受的时候，优先使用分词短语
3）        有情态动词的定语从句不能转为分词短语
4）        定语从句转为分词短语不能产生歧义
9.        加-ing分词作宾语的动词
1）        acknowledge；avoid；admit；enjoy；escape；suggest；assure；advocate；forbid；permit；favor；recommend；resist；risk；involve；deny；include
There is no way to escape doing the work.
2）        give up；credit to；aim at；contribute to；in contrast to；be supposed to；object to；be opposed to；amount to；be exposed/committed/limited/devoted to；lead to；be educated to；be/become accustomed/used to
Since the examination is around the corner, I am compelled to give up doing sports.
3）        aid sb. in doing；prevent/keep/prohibit/save sb. from doing；accuse sb. of doing
    This device is designed to carry sound or to aid in hearing.
4）        be expert at；be good at；criticize ... for；praise ... for；be capable of；be busy；have difficulty in；have trouble in
    The leading actor is expert at conveying his role's fine feeling.
5）        GMAT中常用propose doing，较少用propose to do
    I should propose making a change in the plan.

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10.        不定式的时态和语态
        主动语态        被动语态
一般式        to do        to be done
完成式        to have done        to have been done
进行式        to be doing        --
完成进行式        to have been doing        --
11.        不定式的功能
    不定式在句中可以作主语、表语、宾语、定语、状语和补语。
1）        不定式作主语
不定式作主语时，特别是当不定式短语很长时，往往引入形式主语it，把不定式放在谓语后面：
        It is + 形容词 + 不定式短语
It is beyond my power to sell it cheaper.
        It takes / needs/ requires + 不定式短语
It requires a long time to eliminate the old ideas.
        It is + 名词 + 不定式短语
    It is a shameful thing to have to say.
2）        不定式作表语
在这种结构中，动词不定式用来揭示主语所包含的具体内容。常用的主语有下列名词：
aim，task，duty，goal，work，job，purpose，method，problem，effect，activity，mistake
通常译为：“…就是…”，“…在于…”
Our purpose is not only to conquer nature but also to remake nature.
3）        不定式作定语
        要求不定式作定语的名词
way，ability，power，tendency，capacity，reason，chance，time，method，attempt，opportunity，thing，work，property
To argue in an attempt to come to terms.
        不定式的被动语态作定语
含有“将要”、“有必要”的意思，翻译时可在不定式前加“要”、“待”等词。
To exaggerate the difficulty of something to be done.
        介词 + which + 不定式短语作定语
动词不定式如带有介词，作定语时仍保留介词，常与代词which连用。这种结构仍然是不定式短语，不能视为which引导的定语从句。
He was stumped for words in which to reply.（他被难住了，找不出话来回答。）
        名词前有last、next、序数词或者形容词最高级作定语时，名词后的定语必须使用不定式
The first scientist to do some research on AIDS
12.        不定式的否定形式
1）        not + 不定式：not 置于带to或者不带to的不定式前，属于一般否定
2）        never + 不定式：never置于带to或者不带to的不定式前，强调否定意义
13.        不定式作宾语
不定式作宾语，不定式的动作往往与谓语动词的动作同时发生。
    afford；agree；appear / seem；arrange；choose；claim；come（逐渐）；elect；endeavor；expect；fail；promise；refuse；seek；select；threaten；venture；offer；prefer
    I fail to see the bearing of that remark.（我不明白那句话的真意何在。）
14.        不定式作宾语补语
动词 + 名词短语 + 不定式
advise，allow，cause，compel，enable，invite，inspire，convince，expect，lead，require，use，order
It was a real job to convince them to drop the charges.
15.        疑问代词加不定式
whether/how/when/what/why to do
Sometimes I do not know how to do.
16.        省略to的不定式
1）        动词 + 名词或代词 + do
see，watch，notice，spot（认出），hear，observe，perceive，overhear，feel，smell，let，make
2）        其他
        make do （with/without）（凑合着做）
If we can't get what we want, we shall have to make do without it.
        make believe（=pretend）
Let us make believe that we were Red Indians.
        help （to） do...
We need someone to help do the repairs.
        rather than do ...
I'll do it all by myself rather than ask someone else to help me.
        all sb. do/did is/was do ...
All I do is dream of you.
        might （just） as well do ...
You might just as well go as not.（你去也好，不去也好。）
17.        宾语补语后加不定式
find/deem/make it + adj. + to do
I find it difficult for me to explain this to you.
18.        用不定式表达动作的目的
    用do sth. to do sth，而不用do sth. for doing sth.。
19.        too to结构
    to后主动语态和被动语态都可以使用：
too adj. to do；
too adj. for sb. to do；
too adj. to be done by sb.

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五、平行结构
两个或两个以上互相连接又属于同一层次并有相同句法功能的语言结构叫做平行结构。两个以上的成分构成平行结构，通常只在最后一个并列项之前用并列连词，其他成分之间用逗号连接。但有时也有全用连词的情况，这时是为了修辞的需要，也还有同时用逗号又用连词的情况，以加强语气。
平行结构遵循的四大原则：形式对称、概念对等、功能相同、意思单一。
1.        平行结构的标志
1）        连接词：and，or，but，yet
2）        短语
rather than；not only ... but also ...；from ... to ...；either ... or ...；neither ... nor ...；between ... and ...；both ... and ...；not ... but rather ...；not ... but ...；... as well as ...
2.        形式绝对对称与功能性相对对称
平行结构的并列项通常是同一类型的语言结构（形式绝对对称），但不同类型的语言结构只要属于同一层次并具有相同的句法功能，也可以成为并列项（功能性相对对称）。
    The student answered the question promptly and without mistakes.（功能性相对对称）
3.        重要的平行结构
1）        介词短语和介词短语并列
2）        名词（短语）和名词（短语）并列，尤其是动作性名词（短语）的并列
3）        动词（短语）和动词（短语）并列
4）        分词短语和分词短语并列
5）        现在分词和过去分词并列，作定语
6）        形容词和形容词并列
7）        名词短语可以和what从句并列
8）        副词短语可以和介词短语并列，作状语
9）        than从句可以和介词短语并列
10）        不定式与不定式并列，除第一个不定式的to不能省略外，其他的to可以省略
11）        for doing A，not B
12）        be likely to do ... and be unable to do ... （第二个be不能省略）
13）        不同时态的动词或动词短语并列
14）        宾语从句并列，连词that不能省略：verb. + that ...，+ that ...，and that ...
15）        定语从句并列：n. + in which ... ，in which ...，and in which ...
4.        概念对等原则
1）        具体名词和抽象名词概念不对等
2）        名称名词和动作性名词概念不对等
3）        整体概念和部分概念不对等
4）        泛指概念和特指概念不对等
5.        功能相同原则
1）        不同类型的从句不能并列，因为从句的功能不同。如宾语从句和同位语从句不能并列，定语从句和宾语从句也不能并列
2）        不同功能的从句也不能并列，因为关系词在定语从句中充当不同的成分。
n. + where ... and in which ...不能并列
n. + where ... and who ...不能并列
n. + who ... and whose ...可以并列
6.        意思单一原则
在平行结构中，并列项之间的连接词的连接对象不能引起争议。当连接对象有争议时，有两种修改方法：
1）        根据习惯搭配添加相应的介词
call for A and for B
suspect sb. of doing A and of doing B
2）        改变并列项的位置
the growing demand for housing，traffic congestion，and longer commuting trips =>
traffic congestion，longer commuting trips，and the growing demand for housing

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六、比较结构
1.        比较结构概念对等原则
比较对象之间要有可比性，概念必须对等。
2.        比较结构中的用词原则
1）        代替原则：比较从句中与比较对象重复的名词尽可能用that或those代替
2）        对称原则：比较的对应部分在形式上应尽可能保持对称
3）        语序原则：比较从句使用倒装结构和陈述语序皆可
4）        种属原则：当一个事物（属）与它所属的类（种）比较时，必须用any other把它自身排除在从属范围之外
3.        比较结构中的省略原则
在as或than引导的比较从句中，应遵循以下省略原则。
1）        比较从句与主句谓语相同时，可用do，did或does代替
2）        比较从句系动词be于主句系动词be相同时，可省略be，也可以不省略
3）        主句谓语动词有“助动词（have，has，had，will）”或“情态动词（can，could，may，should）”时，比较从句往往省略verb，保留助动词或情态动词
4）        比较从句与主句的主语和谓语都相同时，可全部省去，常常保留作状语的介词短语或状语从句
5）        比较从句中的主语和主句主语相同时，可以省略
4.        比较从句中的时态和情态
1）        比较从句与主句时态可以一致，也可以不一致
Contrary to the general impression, this quest for import relief has hurt more companies than it has helped.
The economy of Florida is more diversified than it was ten years ago.
2）        比较从句与主句情态可以一致，也可以不一致
I can eat more food than he can.
I eat more food than he can.
5.        倍数的表达
1）        twice的用法
        twice as many/much ... as
Dirt roads may evoke the bucolic simplicity of another century, but financially strained townships point out that dirt roads cost twice as much to maintain as paved roads do.
        twice the n.
Rock samples taken from the remains of an asteroid about twice the size of the 6-mile-wide asteroid that eradicated the dinosaurs have been dated at 3.47 billion years old and thus are evidence of the earliest known asteroid impact on Earth.
        twice what ...
In the 1980’s the rate of increase of the minority population of the United States was nearly twice what it was in the 1970’s.
2）        用动词表达倍数
动词double/triple/quadruple/quintuple可以用主动语态，也可以用被动语态，但不能与as搭配。
Although some officials noted that using machines for farming in China costs more than traditional hand cultivation, the mechanization of farming in the village of Long Bow doubled the corn yield while cutting costs to half those of the previous year.
3）        ... times（或数字）+ as + 形容词或副词 + as ...
A recent national study of the public schools shows that there is now one microcomputer for every thirty-two pupils, four times as many as there were four years ago.
4）        sb. be + 百分数 + more likely to do sth. than to do sth.
According to a recent study, the elderly in the United States are four times more likely to give regular financial aid to their children than to receive it from them.

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6.        比较结构中的习惯搭配
        as + adj. + a/an + n. + as ...
在比较两个人或事物在某方面相同时，使用该结构。
Exercising is as good a way as any to lose unwanted weight.
        more because ... than because ...
Two new studies indicate that many people become obese more because their bodies burn calories too slowly than because they eat too much.
        not ... so much A as B （与其说A倒不如说B）
Child prodigies are marked not so much by their skills as by the fact that these skills are fully developed at a very early age.
        the more ... the more ...（越…，越…）
该结构本为倒装语序，其中be动词常常省略，the more前不能再加修饰语。
A new study finds that the more hostility people show in their behavior and attitudes, the more likely they are to have calcium deposits in the arteries of their hearts.
        no more ... than（与…同样不）；no more than （最多，不超过）
    A man can do no more than he can.
        no less ... than（与…一样）；no less than（多达）
She is no less good at swimming than Mary.
We won no less than 500 in a competition.
        more ... than与less ... than
Four eyes see more than two.
        verb. + more/less of + n.
more of（在更大程度上）和less of（在较少程度上）修饰前面的动词。
I will see less of you in the future.
        ... be more/less likely ... than
Many teenagers undergo stress, but results of a recent study indicate that the patterns of stress that girls experience are more likely to result in depression than are those that boys experience.
        ... be probably not A, but more than likely B
According to scholars, the earliest writing was probably not a direct rendering of speech, but was more than likely began as a separate and distinct symbolic system of communication, and only later merged with spoken language.
        at least as great/big as ...（至少等于）
A representation of an object that is at least as large as the object.
        as much as（几乎等于）
Each year companies in the United States could save as much as $58 billion by preventing illness among employees and gain as much as $200 billion through improved worker performance if they simply provided offices with cleaner air.
        as great as, or greater than ... （至少等于）和as good as, or better than ... （至少好于）
Today we are facing global and technological changes as great as, or even greater than those ever faced before.
        the same as ...
The price is the same as before the war.
        the same to A as to B
Galileo was convinced that natural phenomena, as manifestations of the laws of physics, would appear the same to someone on the deck of a ship moving smoothly and uniformly through the water as to a person standing on land.
        like + n.
强调同一类事物在某方面具有相似性。
        as + 句子
强调动作的相似性。
        just as x, so y
It will not be possible to implicate melting sea ice in the coastal flooding that many global warming models have projected: just as melting ice cubes do not cause a glass of water to overflow, so melting sea ice does not increase oceanic volume.
        x is to y what A is to B
A leading figure in the Scottish Enlightenment, Adam Smith wrote two major books that are to democratic capitalism what Marx’s Das Kapital is to socialism.
7.        语义上比较或对比的结构
语义上具有比较或对比的结构（compared with，below，above，superior to），也要求比较对象具有可比性，在形式上要尽可能对称。
Compared with other Native Americans of the Southwest, the Quechans were singularly uninterested in the accumulation of material wealth or in the crafting of elaborate pottery and basketry.

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七、修饰语、定语从句和状语从句
1.        修饰语使用的四个基本原则
1）        修饰对象必须合理明确
Studies show that young people with higher-than-average blood pressure whose families have a history of high blood pressure are more likely than others to develop a severe form of the condition.（whose跳跃修饰young people）
2）        尽可能贴近修饰对象
3）        跳跃修饰的判断方法
        先就近修饰，再跳跃修饰
        利用主谓一致判断修饰对象
Out of America's fascination with all things antique has grown a market for bygone styles of furniture and fixtures that is bringing back the chaise lounge, the overstuffed sofa, and the claw-footed bathtub.（that从句修饰market）
        利用逻辑关系判断修饰对象
Byron possessed powers of observation that would have made him a great anthropologist and that make his letters as a group the rival of the best novels of the time.（that从句修饰powers）
4）        修饰语的位置改变原则
不能随意改变修饰语的位置，但当修饰对象不清或者修饰对象引起争议时，可以改变修饰语的位置。
The proliferation of so-called cybersquatters, people who register the Internet domain names of high-profile companies in hopes of reselling the rights to those names for a profit, led to passing the Anti-Cybersquatting Consumer Protection Act in 1999, allowing companies to seek up to $100,000 in damages against those who register domain names with the sole intent of selling them later.
in 1999既可能修饰Act也可能修饰passing,导致修饰不清
The proliferation of so-called cybersquatters, people who register the Internet domain names of high-profile companies in hopes of reselling the rights to those names for a profit, led to the passage in 1999 of the Anti-Cybersquatting Consumer Protection Act, which allows companies to seek up to $100,000 in damages against those who register domain names with the sole intent of selling them later.
时间状语in 1999紧靠修饰对象the passage,修饰无歧义
2.        名词的修饰语
1）        名词的修饰语数量要相对有限：尽可能控制在3~4个以内
2）        名词的修饰语要尽可能有层次地分布在名词前或者名词后，并且保持逻辑关系清晰
常用模式为：限定词 + 前置修饰语 + 中心词 + 后置修饰语
3）        名词的前置修饰语中and和逗号的使用
有时可只用逗号而不用and表示并列关系，两者无意义变化。一般来说，多个前置修饰语的语义类别不同，他们之间不能加逗号或and隔开；如果语义类别相同，他们之间可以用逗号或and隔开。
正确用法：the official financial help；a concrete and glass factory；a concrete, glass factory
错误用法：the official and financial help；the official, financial help
4）        修饰语的位置
        放在后面：n + -ed
the people questioned，the only place left，those selected，the material needed，the method adopted，the journalists surveyed
        前后都可：available
        放在前面：increased/increasing + n.
3.        限定性和非限定性定语从句
限定性定语从句对先行词起限制、确定作用，与先行词有着不可分割的关系，它的前面通常没有逗号；非限定性定语从句与先行词之间只有比较松散的关系，通常用逗号与主句隔开。
非限定性定语从句的关系代词which不能指代整个句子，正确的表达如下。
        句子，-ing ...：-ing分词短语作伴随结果状语
Stock levels for domestic crude oil are far lower than in past years, leaving domestic oil prices vulnerable to any hints of oil supply disruptions in the Middle East or any unexpected growth in consumer demand that might be prompted by colder-than-normal temperatures.
        句子 + n.结尾，which ...：which引导定语从句修饰n.
Intended primarily to stimulate family summer travel, the new airfare, which allows both an adult and a child to fly for the price of one ticket, also shortens the advance-purchase requirement for family travel to a minimum of seven days rather than fourteen.
        名词/代词/数词 + of + which/whom ...结构作非限定性定语从句
India is country with at least fifty major regional languages, fourteen of which are officially recognized.
4.        准确使用关系代词和关系副词
关系代词：that（人或物），which（物），who（人，主格），whom（人，宾格），whose（人或物）
关系副词：when，where，why
5.        定语从句习惯搭配
        the period when ...
The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic people has been established by carbon-14 dating, but what is much more difficult to determine is the reason for their decoration, the use to which primitive people put the caves, and the meaning of the magnificently depicted animals.
        a time when ...
At a time when women typically had a narrow range of choices, Mary Baker Eddy became a distinguished writer and the founder, architect, and builder of a growing church.
        since 19XX when ...
Since 1987 when the company went public, sales have nearly doubled, to $243 million last year.
        the year that ...
Which year is the last year that can be divided by 37 in the 20th century?
        the way in which ...
From the earliest days of the tribe, kinship determined the way in which the Ojibwa society organized its labor, provided access to its resources, and defined rights and obligations involved in the distribution and consumption of those resources.
        the way + 句子
Most large companies prefer customized computer software because it can be molded to fit the way a company does business, whereas off-the-shelf software often requires the company to alter its procedures to fit the software.
        an age in which ...
His studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose the concept of an age in which great ice sheets existed in what are now temperate areas.
        the next time + 句子
In its most recent approach, the comet Crommelin passed the Earth at about the same distance and in about the same position, some 25 degrees above the horizon, as will Halley’s comet the next time it appears.
        phenomenon in which ...
El Nino, the periodic abnormal warming of the sea surface off Peru, is a phenomenon in which changes in the ocean and atmosphere combine to allow the warm water that has accumulated in the western Pacific to flow back to the east.

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6.        介词与关系代词连用
关系代词whom和which与一个含有介词的动词短语连用时，介词应该放在关系代词的前面。
Declining values for farm equipment and land, the collateral against which farmers borrow to get through the harvest season, are going to force many lenders to tighten or deny credit this spring.
7.        状语从句的主语
1）        状语从句在主句之前，如果主语相同，任何一个主语都可以用代词表示
2）        主句在状语从句之前，如果主语相同，只有状语从句的主语可以用代词表示
The Olympic Games helped to keep peace among the pugnacious states of the Greek world when they proclaimed a sacred truce for the festival month.
3）        before/after/while doing sth., + 句子，doing sth.的逻辑主语等于句子主语
The caterpillar of the geometrid moth strikes when special tactile hairs on its body are disturbed and, after capturing its prey, holds the victim so that it cannot escape.
8.        时间状语从句
after，when，whenever，while，as，since，ever since，until，once，as soon as
before/after + 句子/短语/doing sth., + 句子：doing sth.的逻辑主语等于句子主语
9.        方式状语从句
as用来引导方式状语从句，含“按照…的方式”或“类似…方式”之意。
Always do to the others as you would be done by.（你希望人家怎样待你，你就要怎样待人。）
10.        目的和结果状语从句
1）        so/such ... that ...：表示结果，such后一般不加抽象名词
Found throughout Central and South America, the sloth hangs from trees by its long rubbery limbs, sleeping fifteen hours a day and moving so infrequently that two species of algae grow on its coat and between its toes.
2）        so/such ... as to ...：表示结果，用于单一主谓结构中，as to的逻辑主语等于句子主语
Climatic shifts are so gradual as to be indistinguishable at first from ordinary fluctuations in the weather.
3）        so that ... + 情态动词 + ...：表示目的
Although the manager agreed to a more flexible work schedule, he said that it must be posted on the bulletin board so that both management and labor will know what everyone is assigned to do.
4）        so that ...（无情态动词）：表示结果
Everyone lent a hand, so that the work was finished ahead of schedule.
5）        so as to：既可以表示目的又可以表示结果，用于单一主谓结构中，as to的逻辑主语等于句子主语
The test questions are kept secret so as to prevent cheating.
11.        条件状语从句
if，only if，unless，as long as，on condition that ...，should（如果/假如） + 主语 + do（原形）/be done
Developing nations in various parts of the world have amassed $700 billion in debts; at stake, should a significant number of these debts be repudiated, is the solvency of some of the world’s largest multinational banks.
if只能引导条件状语从句，表示“如果”，只有whether可以表示“是否”，引导主语从句、宾语从句和表语从句。
In an assessment of the problems faced by rural migrant workers, the question of whether they are better off materially than the urban working poor is irrelevant.
12.        转折与让步状语从句
        although，even though，even if，while，whereas，where
The Immigration Service now has the discretionary power to keep families united even though not all their members meet the five-year residency requirement.
        however much/many/long/great ...：however表示强烈语气
However much United States voters may agree that there is waste in government and that the government as a whole spends beyond its means, it is difficult to find broad support for a movement toward a minimal state.
        特别注意：despite（介词） + 名词短语，不能加句子或doing
Despite massive federal subsidies to public transportation systems and major local efforts to persuade the public to use public transportation, mass transit has been steadily losing patronage to the private automobile for the past thirty years.
13.        原因状语从句
because，as，since，for，now that，if only because（唯一的原因是…），in that
Now that our plan are settled let us proceed.
14.        状语从句的省略
正确形式：连词（when/while/if/unless/although/even/though/even if）+ adj./-ing/-ed（逻辑主语同主句）
Recently implemented “shift-work equations” based on studies of the human sleep cycle have reduced sickness, sleeping on the job, and fatigue among shift workers while raising production efficiency in various industries.
错误形式：连词 + 介词短语/名词短语
特殊情况：once + 介词短语/名词短语；whatever + 名词短语
Once an apolitical confrontation of the world’s best athletes, the Summer Olympics have been increasingly politicized in recent years as the superpowers have denied many of the best athletes’ access to competition.
According to some analysts, whatever its merits, the proposal to tax away all capital gains on short-term investments would, if enacted, have a disastrous effect on Wall Street trading and employment.

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八、词的使用与惯用法
1.        用词的五大基本原则
1）        注意口语和书面语的区别，严格遵循书面语原则
2）        优先选择简洁的表达方式，尤其是简洁的习惯搭配
3）        密切关注词的位置变化，保证词的位置正确
4）        避免词与词在语义上重复
5）        实义词（名词/动词/形容词/副词）不能随意省略、添加或替换
2.        介词的使用
1）        密切关注习惯搭配中的介词是否正确
2）        GMAT常考的介词
about，over，after，before，against，among，between，besides，by，despite，except，for，from，in，into，like，of，on，since，to，under，until，with，within，without，during，including
3）        介词短语的修饰对象一定要明确：作状语，修饰动词；作后置定语，修饰名词，不能引起争议
4）        介词后可以加名词性从句，但不能加完整的主谓结构
3.        动词的使用
1）        完整的主谓结构不能缺少作谓语的动词
2）        动作之间逻辑关系要合理
3）        谓语动词与分词不能混淆
4）        当怀疑动词有错时，可按以下顺序进行分析
主谓一致，情态，语态，语气，时态
4.        形容词和副词的使用
1）        形容词和副词的修饰对象一定要明确
2）        形容词和副词不能混淆
3）        形容词短语在句首时逻辑主语等于句子主语（contrary to除外）
Contrary to popular belief, victors in the ancient Greek Olympic Games received cash prizes in addition to their laurel wreaths.
5.        代词的使用
1）        避免代词指代不清，修改方法如下
        重复代词指代的对象
        用such + n.或者指示代词this/that/these/those + n.代替代词
        用一个名词概括代词所指代的对象
2）        代词一致性原则，相同的代词指代对象要一致
3）        it和one的区别
it指单数名词或不可数名词，one指单数名词短语的核心词
4）        that和those用来代替前面提过的人或物，以避免重复
5）        代词it/this/that不能指代整个句子
6）        代词this/that/these不能单独充当主语，必须加上名词才能作主语
7）        “do + 代词”永远错，正确表达为：do so
6.        名词的使用
1）        个体名词（表示一类人/事/物）和群体名词（表示若干个体组成的集体）为可数名词，有复数形式，而物质名词和抽象名词不可数名词，一般不用复数形式
2）        动作性名词和动名词-ing形式的区别
动作性名词（comparison，combustion，sale，increase，rise）强调动作的结果和状态，动名词形式（comparing，burning，selling，increasing，rising）强调动作本身
3）        名词所有格
        ’s属格主要用于有生命的名词，也用于群体/时间/天体/物理/区域/机构等名词
        of属格可用于有生命或无生命的词
        of ... ‘s属格，GMAT不接受这一双重所有格
        ’属格，主要用于以-s后缀的复数名词，如monkeys’
4）        名词的泛指与特指
        名词前加冠词the、物主代词或其他限定词表示特指
        名词前加不定冠词a/an或不加限定词（可数名词用复数）表示泛指
5）        名词短语的核心词不能与修饰成分中的名词混淆
如A of B中，A是核心词，不能变成B of A
6）        名词的逻辑对应
        复数代词或such/these/those + 复数名词，对应已经出现过的复数名词
        单数代词或the + 单数名词/such a/an + 单数名词，对应已经出现过的单数名词

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九、逻辑表达
1.        简洁有效原则
1）        将从句简化为短语
2）        将短语简化为词
3）        使用省略手段
2.        意思合理原则
1）        前后文逻辑意思不矛盾
2）        不违反生活事理、科技常识
例如，下面例句中的were destroyed和heavily damaged不可能同时发生在同一建筑物身上，所以应该使用or，而不是and。
Some buildings that were destroyed or heavily damaged in the earthquake last year had been constructed in violation of the city’s building code.
3）        逻辑搭配必须合理
要避免主谓搭配不当，动宾搭配不当，主表搭配不当，副词和动词搭配不当，形容词和名词搭配不当。
3.        重心保持原则
1）        原句的合理意思不能变
2）        主次意思不能随意颠倒
原句的主从关系不能毫无根据地改变，即次要成分不能随意改为句子的主要成分，同时句子的主要成分也不能随意下降到从属地位，作修饰语使用。
3）        定语和状语一般不能互相改变
4）        整体和局部一般不能互相改变
例如possibility that sb./sth. do ... 不能改为possibility of doing ...。
4.        意思单一原则
1）        保证修饰语的修饰对象单一明确
例如：在A, -ing, B + verb. ...中，-ing修饰的对象有争议，可改为定语从句，从而只能修饰A。
2）        在平行结构中，保证连接词连接对象的单一明确
3）        单义词优先，避免使用容易引起歧义的多义词
4）        通过词的位置改变保证意思的单一性
        在A and B, who ...结构中，who不能仅仅指B，必须同时指A和B；如果要保证who指B，应改为B, who ..., and A。
Published in Harlem, the Messenger was owned and edited by two young journalists, A. Philip Randolph, who would later make his reputation as a labor leader, and Chandler Owen.
        all ... do not do ...应该为not all ... do ...。
The Immigration Service now has the discretionary power to keep families united even though not all their members meet the five-year residency requirement.