2.5　抓主干的方法

一个句子的主要意思，一般存在于主干里面（同位语从句是例外，详见2.5.5）。因此，理解句子的本质就是能够快速找出并理解句子的主干。那何为主干？主干可以理解为由一个或几个含有主谓宾的简单句构成的句子。如何从纷繁复杂的长难句中找到主干，是我们理解SAT长难句的第一步。

那如何找句子的主干呢？一个句子可以没有宾语，甚至可以没有主语（祈使句），但是一定要有谓语动词。因此我们判断一个句子的成立与否，首先就是要找到句子里的谓语动词。

2.5.1　名词或相当于名词的词开始的句子，如何抓主干

抓主干的关键就是找到谓语动词，SAT长难句里最常见的谓语动词有动词原形、动词过去式和动词的三单形式。主干一般包含主谓宾，至于主语从句和宾语从句，它们都属于名词性从句。主语从句在考试中出现的比较少，这里不专门论述。宾语从句，一般不对中国学生的理解构成障碍，且宾语从句里包含了丰富的信息，所以也把主语从句和宾语从句划为主干。如果一句话以名词或相当于名词的词或句子开始，它可能就是主语，这个时候要找到谓语动词，然后就可以确定主干。

【解析】从前向后读该句，句中went是动词的过去式，是谓语动词，可以做谓语。前面有代词I作主语，后面和to一起有her studio这个名词作宾语，故主谓宾凑齐，所以I went to her studio是主干。

【答案】I went to her studio in Redcliffe Square feeling uncomfortable and even embarrassed，thinking how awful to be an artist，having to put up with prospective buyers coming to gape，whereas writers never need to see anyone read their books.

【解析】从前向后读该句，句中wrote是动词的过去式，是谓语动词，可以做谓语。前面有代词he作主语，后面the call这个名词作宾语，故主谓宾凑齐，所以He wrote the call是主干。

【答案】He wrote the call for the 1853 convention in Rochester，New York，which demanded not only that women be paid equally with men for their work，but also that women，including married women，have equal rights with men in the ownership and disposition of property.

【解析】从前向后读该句，句中assumed是动词的过去式，是谓语动词，可以做谓语。前面有名词biologists作主语，后面是由that引导的宾语从句，故主谓宾凑齐。因此整个句子Biologists assumed that this seemingly purposeless activity had little effect on animal development，was not a distinct form of behavior，and was too nebulous a concept either to define or to study都为主干。

【答案】Biologists assumed that this seemingly purposeless activity had little effect on animal development，was not a distinct form of behavior，and was too nebulous a concept either to define or to study.

【解析】从前向后读该句，句首名词a dog后紧跟着who引导了一个定语从句（详见4.1.3），故需要跳过该从句，继续往后找谓语动词，发现句中might是动词的过去式，是谓语动词，可以做谓语。前面有名词A dog作主语，和后面的动宾结构一起构成谓语和宾语，故主谓宾凑齐，句子主干为A dog might easily worry about our consciousness or lack thereof。

【答案】A dog who did comparative psychology might easily worry about our consciousness or lack thereof，just as we worry about the consciousness of a squid.

【解析】从前向后读该句，句中系动词was是动词的过去式，是谓语动词，可以做谓语。前面有代词it作主语，后面about weight and brute power做表语，也相当于是主谓宾，所以It was about weight and brute power是主干。

【答案】It was about weight and brute power—beautifully machined heavy steel，burnished bronze，polished copper pipes，ornamental cast iron—everything built，with no expense spared，to withstand great pressures and last any number of lifetimes.

2.5.2　副词连接词引导的句子，如何抓主干

如果长难句以副词连接词开始且引导半个句子，一般是状语从句，可以跳过该半句，从后半句找主干。常见副词连接词有if、since、because、as、when、while、where、until、although、though、whereas、as soon as等。

【解析】从前向后读该句，由于逗号前的句子由连词though引导，所以该半句不能是主干，一般是状语成分（详见第5章）。再往后读到谓语动词have，是动词原形，可以构成谓语，且前面有Native American people这个名词作主语，故可以构成主干。该句主干为Native American people have had to cope just like everyone else。

【答案】Though often equipped with a shovel shaped incisor tooth，eyes with epicanthic folds，or an extra molar cusp，Native American people have had to cope，for the last forty thousand years or so，just like everyone else.

【解析】从前向后读该句，由于逗号前的句子由连词as soon as引导，所以该半句不能是主干。再往后读到谓语动词feel和are，是动词原形，可以构成谓语。且前面有most people这个名词作主语，后面由and连接了两个谓语，它们共同构成主干。该句主干为most people feel out of their depth and are at a loss as to what to make of the scene，the book，or the painting。

【答案】As soon as purely aesthetic elements predominate and the story of John and Susie grows elusive，most people feel out of their depth and are at a loss as to what to make of the scene，the book，or the painting.

【解析】从前向后读该句，由于逗号前的句子由连词when引导，所以该半句不能是主干，并且中间还包含了由两个逗号隔开的分割结构（详见8.2）as in A Connecticut Yankee in King Arthur's Court。再往后读到谓语动词achieved，是动词的过去式，可以构成谓语，且前面有he这个名词作主语，后面有名词such a masterpiece of vulgarity作宾语，故可以构成主干。该句主干为he achieved such a masterpiece of vulgarity。

【答案】 When，as in A Connecticut Yankee in King Arthur's Court，he gave full rein to his fancy，he achieved such a masterpiece of vulgarity as the world has never seen.

2.5.3　伴随状语引导的句子，如何抓主干

如果长难句以V+ing、V+ed、adj或介词短语开始且引导半个句子，且这些成分附近没有可以修饰的名词，且它们的逻辑主语和后面主干主语一致，则它们一般是伴随状语成分（详见5.1.4），可以跳过该半句，从后半句找主干。

【解析】从前向后读该句，由于逗号前的半句由V+ing，即foraging、cultivating和gazing引导，且附近没有可以修饰的名词，一般是伴随状语成分。再往后读到谓语动词epitomizes，是动词的三单形式，可以构成谓语，且前面有Henry David Thoreau这个名词作主语，后面有名词a long-standing American worship作宾语，故可以构成主干。该句主干为Henry David Thoreau epitomizes a long-standing American worship of nature。

【答案】Foraging near the hut that he built himself，cultivating beans whose properties invited speculation，gazing into the depths of Walden Pond，Henry David Thoreau epitomizes a long-standing American worship of nature.

【解析】从前向后读该句，由于逗号前的半句由V+ed，即isolated、warmed和starved引导，且附近没有可以修饰的名词，一般是伴随状语成分。再往后读到谓语动词could，是动词的过去式，可以构成谓语，且前面有the life-forms这个名词可以作主语。故该句主干为the life-forms of Vostok could teach scientists how life might persist in Europa's frigid climate。

【答案】Isolated from light，warmed only from below，starved of nutrients，the life-forms of Vostok could teach scientists how life might persist in Europa's frigid climate，where temperatures average minus 250 degrees Fahrenheit.

【解析】从前向后读该句，由于逗号前的半句由形容词chauvinistic引导，且附近没有可以修饰的名词，一般是伴随状语成分。再往后读到谓语动词come，是动词原形，可以构成谓语，且前面有we这个代词作主语，故可以构成主干。该句主干为we come to associate night dwellers with people up to no good。

【答案】Chauvinistic about our human need to wake by day and sleep by night，we come to associate night dwellers with people up to no good，people who have the jump on the rest of us and are defying nature，defying their circadian rhythms.

【解析】从前向后读该句，由于逗号前的半句由介词without引导，所以该半句不能是主干。再往后读到谓语动词can，是动词原形，可以构成谓语，且后面有we这个代词作主语（该句为倒装句，详见8.3），故可以构成主干。该句主干为how can we penetrate to the core of meaning in an expression of art？

【答案】Without some knowledge of language，of history，of inflection，of the position of the storyteller within the group，without a hint of the social roles played by males and females in the culture，without a sense of the society's humor or priorities—without such knowledge，how can we，as reader or listener，penetrate to the core of meaning in an expression of art？

2.5.4　可以有多个主干

长难句还可以由并列连接词and、but或特殊标点符号如分号、冒号等连接的几个简单句子构成。这些句子之间可以根据连接词的逻辑关系相互推理或忽略（详见3.1），从而更加容易理解整个句子。

【解析】从前向后读该句，发现句子中有两个谓语动词，即有两个简单句，且由连词and连接，故可以有两个主干。它们的谓语动词都为were，也都是动词的过去式，可以构成谓语。所以该句主干为Aristocrats were often exempt from societal strictures和working-class women were usually looked down on as not being"respectable"for their efforts as workers。

【答案】Aristocrats were often exempt from societal strictures that bound the middle class，and working-class women were usually looked down on as not being"respectable"for their efforts as workers.

【解析】从前向后读该句，发现句子中有三个谓语动词proliferated、disappeared和returned，即有三个简单句，且由两个连词and和but连接，故可以有三个主干。所以该句主干为Representations of Eros proliferated in that Hellenistic period，childhood disappeared from art together with the other Hellenistic themes，和the subsequent Romanesque art returned to the rejection of the special features of childhood。

【答案】Representations of Eros，the Greek child god of love，proliferated in that Hellenistic period，but childhood disappeared from art together with the other Hellenistic themes，and the subsequent Romanesque art returned to the rejection of the special features of childhood.

【解析】从前向后读该句，发现句子中有两个相同的谓语动词produces，即有两个简单句，且两个句子由分号隔开，故可以有两个主干。所以该句主干为Anapproaching body produces one kind of emotional line和the meeting of two forcesproduces visual，kinesthetic，and emotional effects。

【答案】An approaching body produces one kind of emotional line，a receding or departing body another；the meeting of two forces produces visual，kinesthetic，and emotional effects，with a world of suggestibility around them like a penumbra that evokes many ideas and emotions whenever these forms are manipulated.

2.5.5　例外

部分长难句的主要意思不在主干，而在修饰成分里，尤其是在主干非常短的时候，比如含有同位语从句（详见4.2.2）的句子等，句子的核心意思不在主干，而在同位语从句里面，要特别注意。

【解析】该句主干为this serves to confirm the view of one Victorian man。但是该句主干里没有实质性的意思，主要意思在同位语从句whereas his mother had confidently joined in the family auctioneering business，the increased division of the sexes had seen the withdrawal of women from business life中，需要特别注意。

【解析】该句主干为I went to her studio。但是该句主干里没有实质性的意思，主要意思在伴随状语成分feeling uncomfortable and even embarrassed，thinking how awful to be an artist，having to put up with prospective buyers coming to gape中，在主干比较短的时候，需要特别注意。

相信同学们通过以上例子的练习，已经对找主干有些感觉了吧。请再接再厉！