说明：
本文是在国内GMAT考生中广为流传的PREP语法笔记整理而成。这些PREP题目，包括了老PREP和新PREP中的各2套共493道题目。我们把这些题目，按20道题目一组，创建了25个练习册，方便大家先做后看。
注意：此部分解析为非官方、非专业老师整理的解析。
161.
Deserts are inhabited with several distinct animal species, with each their own method of adapting to long periods of moisture shortage.
A. with several distinct animal species, with each their
B. with distinctly several animal species, each with its
C. by several distinct animal species, each with its
D. by several distinct animal species, having each its
E. by several distinct animal species, that each has their
题目释义: Deserts are inhabited by serveral distinct animal species, each with its own…
沙漠里居住这几种不同的动物，每一种都有其自身的方法长期适应湿气不足的环境。
考点:
主谓一致，固定搭配（idiom）, 逻辑表达（Logical Predication）
1. with与each可以引导独立主格结构，独立主格结构的形式，需要注意其所表达的逻辑意思。
2. 主语是deserts，谓语inhabit的被动态，each 引导独立主格结构，进一步说明每一类animal species均有的一中特性。With介词短语修饰each，表示具有某种性质。
3. inhabit vt 居住于. 固定搭配：be inhabited by
e.g: The woods are inhabited by many wild animals.
4. 独立主格
选项分析:
(A) inhabited with搭配错误；each对应复数their错误；each型独立主格形式错误。
(B) inhabited with搭配错误；distinctly副词修饰形容词several逻辑错误。
(C) Correct。
(D) having现在分词短语做状语修饰谓语动词与主语deserts错误。
(E) each对应复数their错误；that无法引导非限定性定从引导词；没有必要that each互成同位语，each型独立主格只需要直接跟在逗号后面即可。
补充说明:
1. method的用法：
(1) method of/for (doing) something 优于 the method to：
"a method of protecting would be more idiomatic than a method to protect" 这是OG10-39解释中的一句话.
例句：
Today’s methods of birth control make it possible for a couple to choose whether or not to have a child. effective methods for the storage and retrieval of information
例题：
137. Coronary angiography, a sophisticated method for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses x-rays to observe cardiac function.
(A) for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(B) for diagnosing coronary disease involving the introduction of a dye into the arteries of heart, is now administered selectively, because of using
(C) for diagnosing coronary disease, involves the introduction of dye into the arteries of the heart and is now administered selectively, because it uses
(D) to diagnose coronary disease that involves the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(E) to diagnose coronary disease involving the introduction of a dye into the arteries of the heart, which is now administered selectively, uses
Key: C
(2) 但是method的内容则可以用不定式表示：the method/way is to do…
OG12-11. There are several ways to build solid walls using just mud or clay, but the most extensively used method has been the forming of bricks out of mud or clay, and, after some preliminary air drying or sun drying, they are laid in the wall in mud mortar.
(A) the forming of bricks out of mud or clay, and, after some preliminary air drying or sun drying, they are laid
(B) forming the mud or clay into bricks, and, after some preliminary air drying or sun drying, to lay them
(C) having bricks formed from mud or clay, and, after some preliminary air drying or sun drying, they were laid
(D) to form the mud or clay into bricks, and, after some preliminary air drying or sun drying, to lay them
(E) that bricks were formed from mud or clay, which, after some preliminary air drying or sun drying, were laid
Key: D (以平行判题)
162.
Such orb-weaving spiders like the argiope build webs in an essentially wheel-like structure, with an outer rim and a number of spokes emanating from the hub.
A. Such orb-weaving spiders like the argiope build webs in an essentially wheel-like structure
B. Such orb-weaving spiders as the argiope builds webs with what is essentially a wheel-like structure
C. The argiope spider, in the same way as other orb-weaving spiders, build webs in a structure that is essentially wheel-like
D. Orb-weaving spiders such as the argiope build webs that are essentially wheel-like
E. Like other orb-weaving spiders do, the argiope builds webs as essentially wheel-like
题目释义：Orb-weaving spiders such as the argiope build webs that…. ,with ……
球形织网的蜘蛛如argiope，所织的网很像车轮：有个外部的圆边，还有从中心发散到外沿的很多个类似轮辐的线。主语是the argiope，谓语动词是build，that引导定语从句修饰web,with 引导独立主格结构，补充句子含义。
考点:
固定搭配(idiom)，比较对等，主谓一致
1) like不举例，举例用such as
2) like 用于比较结构中时，做介词用其后不能加句子，like sth do是错误结构
3) such A as B的结构，谓语单复数情况与A一致，因为B只是举例的内容。
例：OG11#55: Doctors generally agree that such factors as cigarette smoking, eating rich foods high in fats, and alcohol consumption not only do damage by themselves but also aggravate genetic predispositions toward certain diseases.
选项分析:
(A) 举例用such as，such … like搭配错误；with an outer rim短语修饰前面整句，逻辑主语是orb-weaving spiders错误。
(B) 主谓不一致，such spiders as … 谓语对应bulid（用such spiders as和spiders such as都可以）；以某种形状建造应该是build in certain structure；build with *** structure搭配错误；what is essentially a wheel-like structure表达累赘
(C) 比较the argiope spider和other orb-weaving spiders用in the same way as连接错误，应用like，in the same way as用于比较两个事件；build主谓不一致；webs in a structure that is wheel-like累赘，直接webs that are wheel-like即可
(D) Correct；with型独立主格可以伴随情况，在此伴随修饰that are essentially wheel-like
(E) 表比较时，like后只能加名词，不能加动词do；build…as + adj.搭配错误
补充说明:
1. in the same way as/that/(that)的使用方式：
大全312. Because new small businesses are growing and are seldom in equilibrium, formulas for cash flow and the ratio of debt to equity do not apply to them in the same way as to established big businesses.
大全884. The use of gravity waves, which do not interact with matter in the way electromagnetic waves do, will, it is hoped, enable astronomers to study the actual formation of black holes and neutron stars.
GWD26-Q3: Deliberately imitating the technique of Louis Armstrong, jazz singer Billie Holiday used her voice in the same way that other musicians use their instruments, in that she ranged freely over the beat, flattening out the melodic contours of tunes, and, in effect, recomposed songs to suit her range, style, and artistic sensibilities.
GWD30-Q16: Researchers are using computer images to help surgeons plan difficult operations and to develop programs that will work for doctors and nurses in the same way that flight simulators do for pilots, letting medical personnel practice their techniques and test their reflexes before they ever see a patient.
Prep1-118. Scientists have found new evidence that people initially register emotions such as sadness or anger in much the same way as they experience heartburn--by monitoring what's going on within their bodies.
163.
Because there are provisions of the new maritime code that provide that even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas, they have already stimulated international disputes over uninhabited islands.
A. Because there are provisions of the new maritime code that provide that even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas, they have already stimulated
B. Because the new maritime code provides that even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas, it has already stimulated
C. Even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas under provisions of the new maritime code, already stimulating
D. Because even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas under provisions of the new maritime code, this has already stimulated
E. Because even tiny islets can be the basis for claims to the fisheries and oil fields of large sea areas under provisions of the new maritime code, which is already stimulating
题目释义：Because….., it has already stimulated….
由于新的海事法规定，即使是微小的小岛，也可以要求在很大的海域拥有捕鱼和建立石油的权利，它已经刺激了无人居住的岛屿国际争端。
考点:
指代一致，逻辑意思、简洁(Concise)
1. 指代要注意
1) 是否会出现多个可能的指代对象，造成语义模糊；
2) 指代明确的情况下，逻辑含义是否正确。
2. this指代除非特别明显，否则通常不可单独指代，需要加上具体名词（即this做为adjective），如this code等，才是正确的指代形式。同理those/these在指代时，通常均需补充名词。
4 that\those用于比较结构中，避免重复，和单独指代要区别开来
5. which只能指代前面出现过的名词而不能指代整个句子，which指代前面句子表达的意思常作为伴随副词的混淆选项出现。
6. 逻辑上，句子总会有属于自己最合理的中心，因此而不能随意改变句子重心。
7. provision n. 条款（provide的名词形式，provide有“规定”的意思）
选项分析:
(A) 选项wordy: there be在此处冗余；provision和provide语义重复；they指代不清，有指代islets的歧义
(B) Correct；Because原因状语从句，it主从对位指代the new maritime code，谓语动词：stimulate，完成时态，符合逻辑。
(C) 原本的主句被改成了修饰成分,句子重心改变；stimulating逻辑主语成了tiny islets错误；由于前面是主系表结构，所以stimulating不做伴随结果状语，割裂前后因果关系；under provisions of the new maritime code错误修饰sea areas
(D) this不可单独指代，应加上具体名词；under provisions of the new maritime code错误修饰sea areas
(E) 缺少主谓结构，题目释义不完整：原因状语从句，+which引导的非限定性定语从句。句子重心改变，stimulating成为修饰成分；时态由完成时变为现在进行时，already是完成时态的标志词之一，逻辑意思不正确；under provisions of the new maritime code错误修饰sea areas
补充说明：
OG12-113解释：
Logical predication; Grammatical construction
In this sentence, the there are … that … construction contributes nothing more than unnecessary words. Th e sentence needs to make clear whether provisions or code is the subject of the main verb stimulated.
A. The there are … that … construction is unnecessarily wordy; in the predicate nominative instead of the subject position, provisions is not an obvious referent for the pronoun they.
B. Correct. In this sentence, the new maritime code is clearly the antecedent of it in the main clause and thus the subject of has already stimulated.
C. Under provisions of the new maritime code is a misplaced modifier, seeming to describe sea areas; the sentence does not make clear what is stimulating … disputes.
D. The referent of this is unclear.
E. The sentence is a fragment, opening with a dependent clause (Because … code) and concluding with a relative clause, but lacking a main, independent clause.
The correct answer is B.
现在分词伴随状语的正反向考法 -- by dxwei2008
GMAT语法中常常考查前一个分句的整体对后面一个对象的作用结果，一般认可的正确答案是使用现在分词做伴随状语。另外还有一种应用情况是，两个动作同时发生。在平时的语法中，我们常常使用连词and来连接两个动作，可是在GMAT语法中常常使用伴随状语。老鱼在它的讲座里举的一个例子就是：
She is sitting on the tree and reading a book. (一般语法)
She is sitting on the tree, reading a book.(GMAT语法)
所以我们在以下两个情况下要使用伴随状语
1. 前一个分句的整体对后面某一个对象的作用
2. 两个同时发生的动作 ，补充主语的动作
一、 正向考法
正向考法就是要你识别出前一个分句是从整体上对后一个分句的宾语发生作用。例如：
He scored 100, making him the best student.
这里的making动作的逻辑主语就是前一个分句的整体。既不是前分句的主语也不是前分句的宾语，所以只可以使用伴随状语。
二、 反向考法
既然一个考点可以正向考，如果不反向也考一考就没有难度了。反向的考法是，当前一个分句本来没有对后一个分句的宾语造成任何作用，题目却不断地引诱你去这样做。例如：
He went into the classroom and sat on the chair.(逻辑上很合理，只有进了教室才可以坐在椅子上)
ETS的干扰选项：He went into the classroom, sitting on the chair.(逻辑上就很荒谬了，在进教室这个动作发生的时候，他一直坐在椅子上)
He scored 100 in the 1st test and scored 99 in the 2nd test.(逻辑上很合理)
ETS的干扰选项：He scored 100 in the 1st test, scoring 99 in the 2nd test.(逻辑上很荒谬，第一次考了100导致第二次考99)
关于these的单独指代
prep2-34 讨论帖http://forum.chasedream.com/GMAT_SC/thread-336111-1-1.html
Besides adding complementary flavors to many foods, hot sauces stimulate the release of endorphins in the brain, just as exercise does, and these have a pain-relieving effect like morphine's.
(A) hot sauces stimulate the release of endorphins in the brain, just as exercise does, and these have a pain-relieving effect like morphine's
(B) hot sauces stimulate the release of endorphins in the brain, like exercise, and they have a pain-relieving effect that is like morphine
(C) hot sauces and exercise both stimulate the release of endorphins in the brain, and they have a pain-relieving effect like morphine
(D) the release of endorphins in the brain is stimulated both by hot sauces and exercise, and they have a pain-relieving effect like morphine's
(E) the release of endorphins in the brain is stimulated by hot sauces, just as with exercise, and these have a pain-relieving effect like that of morphine
Key：A à these指代endorphins。
小结：
1) 除非很明显，this\these不能单独指代，要补出后面的名词。
2) they指代前面出现的对象，these指代离它最近的对象，指代都要满足逻辑符合，主谓一致的要求。
3) 当they前出现两个以上主谓符合的对象时，视其为指代不清。而these前出现两个以上主谓符合的对象时，可以就近指代，比they更佳。
164.
Mixed with an equal part of water, ethylene glycol, a compound commonly used as an automotive antifreeze, is effective at temperatures as low as –30 degrees Fahrenheit.
A. temperatures as low
B. temperatures so low
C. as low temperatures
D. as few
E. as little
题目释义:Mixed with …, ethylene glycol, a compound…, is effective at temperature as low as…乙二醇，作为混有同样体积的水的化合物，通常作为汽车防冻剂使用，在低达华氏30度的时候才有效。
考点:
1. 比较结构as adj. a noun. as... ：
as....as之间是可以加 adj+noun的，不过好像只限于几种形式(张振邦)：
as+adj.+不定冠词+单数可数+as I haven't seen as old a car as this for years.
as+adj.+零冠词+不可数名词+as 对应 prep2-9 (见类似题链接)
as+adj.+零冠词+复数可数名词+as I don't smoke as expenesive cigarettes as those.
2. as adj. (a) noun. as = (a) noun. as adj. as，其中第一个as是adv.
选项分析:
(A) Correct；主语是ethylene glycol，mixed过去分词前置修饰有被动的含义，Mixed的逻辑主语即句子的主语ethylene glycol。a compound 引导同位语从句，Be effective为句子谓语。
(B) so as只用于否定句中。
(C) at后面缺少名词作宾语
(D) at后面缺少名词作宾语；few不能形容温度
(E) at后面缺少名词作宾语；little不能形容温度
类似题链接：
prep 2-9 The Environmental Protection Agency frequently puts mandatory controls on toxic substances that present as little risk as one in a million chances to cause cancer.
(A) as little risk as one in a million chances to cause
(B) as little risk as one chance in a million of causing
(C) as little risk as one chance in a million that it will cause
(D) a risk as little as one chance in a million for causing
(E) a risk as little as one chance in a million for it to cause
Key: B
如果D和E改成a risk as little as one chance in a million of causing也就对了
165. (OG10-243)
Some scientists have been critical of the laboratory tests conducted by the Federal Drug Administration on the grounds that the amounts of suspected carcinogens fed to animals far exceeds those that humans could consume
A. far exceeds those that humans could consume
B. exceeds by far those humans can consume
C. far exceeds those humans are able to consume
D. exceed by far those able to be consumed by humans
E. far exceed those that humans could consume
题目释义：Some scientists have been critical of…. on the grounds that….. ……
一些科学家已经对FDA所进行的实验室试验感到不满，因为试验中动物所食用的可疑致癌物的量已经大大超过人类可能消耗的数量。
考点:
比较对等，主谓一致
1）far exceed引导比较结构要求比较对象要对等。
2）can和be able to不需要从意思上（能力还是可能性）加以区分，只要注意时态看哪个更合适，又没有明显错误就行；http://forum.chasedream.com/GMAT_SC/thread-121279-1-1.html
3）Be critical of ..不满。
选项分析:
(A) amounts 与exceeds主谓不一致。
(B) amounts 与exceeds主谓不一致；exceed by far不如far exceed简洁
(C) amounts 与exceeds主谓不一致；those后面的关系代词that可以省，但在此为了句意更加清晰而补出
(D) exceed by far不如far exceed简洁；those able to be consumed好像在说食品能够主动地被人吃，逻辑上很荒谬；be consumed by 被动语态，wordy
(E) Correct；主语是Some scientists，谓语是have been critical of，on the grounds that引导原因状语从句；can和could不仅仅在时态上有差别，在肯定程度上也有差别，could语气较弱，两者间区别在本题不成考点；因为those的存在，that的补出使得定语从句更为清晰，即便that在定从中做宾语。
补充说明：
10-243解释：
Choice E is best. The plural verb exceed agrees in number with its subject, amounts, and the phrase those that humans could consume conveys the intended meaning clearly and without unnecessary wordiness.
In choices A, B, and C, the singular exceeds does not agree in number with its plural subject, amounts.
Choices B and C omit the conjunction that -- an omission that is grammatically acceptable, but in the case of this sentence diminishes clarity.
In D, the use of the passive voice in the phrase those able to be consumed by humans is unjustified, as it increases wordiness while stating the meaning less precisely: it is accurate to call humans "able,' but not to call those [amounts] "able."（食品能主动地被人吃）
Ets自己说，主动比被动要好，因为被动说起来罗嗦，而且表达不够准确( be able to be done 永远错)
166.
The period when the great painted caves at Lascaux and Altamira were occupied by Upper Paleolithic peoples has been established by carbon dating, but what is much more difficult to determine are the use to which primitive peoples put the caves, the reason for their decoration, and the meaning of the magnificently depicted animals.
A. has been established by carbon dating, but what is much more difficult to determine are
B. have been established by carbon dating, but what is much more difficult to determine are
C. have been established by carbon dating, but that which is much more difficult to determine is
D. has been established by carbon dating, but what is much more difficult to determine is
E. are established by carbon dating, but that which is much more difficult to determine is
题目释义：The period …. has been established….., but what is much more difficult to determine is ………..
旧石器时代的人居住在位于Lascaux 与Altamira的巨大的壁画洞的时期已经通过碳测时法确认，但更难确定的是原始人使用什么工具开凿石洞，为什么他们要装饰以及这些华丽的被描绘出的动物所代表的含义。
主语：The period，谓语动词：be establish, 完成时态符合逻辑，when引导时间状语从句修饰主语。but 引导并列句子，what引导主语从句，谓语动词为be difficlut的比较形式，use ,reason, meaning并列做该部分宾语。
考点：
主谓一致：
1. what引导的名词性从句中从句谓语动词的单复数情况：
what后面“什么时候用单数,什么时候用复数”根据动词后面的名词的单复数来定.
2. what引导的名词性从句做主语时，主句谓语动词用单数一定是正确的：
********有时也参照下面的单复数规则：
(1)What在从句中做主语，主句谓语由what从句的谓语决定。
1) What is difficult to understand is A.；What are difficult to understand are A and B.
(2)what在从句中做宾语，主句谓语由主句表语/宾语决定what they want are XX,XX&XX。
2) What his father left him are a few English books.
3. carbon dating 碳(14)测定年代（名词）
选项分析:
(A) but后分句谓语应该用单数形式is，what is difficult的is决定主句谓语用单数is the use to ….
(B) The period和have主谓不一致；but后分句谓语应该用单数形式is
(C) The period和have主谓不一致; that which=what，用what更为简洁
(D) Correct；what is difficult的is决定主句谓语用单数is the use to ….
(E) The period和are主谓不一致; 随意改变句子时态，完成时变现在时；that which 相当于一个从句中两个主语，题目释义错误
补充说明：
1. 以who, why, how, whether或that引导主语从句，谓语动词用单数
例：Why she did this is not known.
2. 前面应被后面替换小结：
which that, that which, the thing that= what
not any = no
not ever = never
which is that=that
the only thing that=all (the only thing that has to be done è all one has to do)
at the time after=after
while being=as (as表过程，随着…)
A is what is the B 中what is可以省略, A is the B
wanting to do=to do
what the effects=the effects
otherpeople/things=others
that of his own=his own (前者双重所有格)
something of whom=whose sth.
but instead=but (windmaple: but后面接名词是不能有instead的，因为but是介词；但是如果but后面接动词就变成了连词，中间加副词instead没问题。例老prep SC1 73：Evolutionary psychology holds that the human mind is not a "blank slate" but instead comprises specialized mental mechanisms that were developed to solve specific problems human ancestors faced millions of years ago.)
with the exception of = except
up until=until (until已经包括了up的含义。
until: conj.(=up to the time when)到...时为止；
prep.（介词）Up to the time of；Before (a specified time):用在否定句)
with none of = without
but still=but
wanting to do=to do
different from that which=different than (不同于different from(用different from正确))
His way of living is different than ours.他的生活方式跟我们的不同。
German cars are different than ours.德国造的汽车和我们的不一样。
You look different than before.你看上去跟从前不同了.
date at which = when
in the event that = if
类似题链接：
大全851. The work of mathematician Roger Penrose in the early 1970s, on the geometry of what are called aperiodic tiles, turned out to describe the architecture of a previously unknown class of crystals.
(A) what are called aperiodic tiles, turned out to describe
(B) what is called aperiodic tiles, describes
(C) aperiodic tiles, describing
(D) so-called aperiodic tiles, describe（A）
(E) aperiodic tiles, it turned out to describe
key: A. what从句“什么时候用单数,什么时候用复数”根据动词后面的名词的单复数来定。
167.
On August 13, 1868, the warship U. S. S. Wateree, anchored in the harbor of Arica, off the coast of what is now northern Chile, rode on the crest of a tsunami (seismic sea wave) and coming to rest in the Atacama Desert, it was some three miles up the coast and almost two miles inland from its initial anchorage.
A. rode on the crest of a tsunami (seismic sea wave) and coming to rest in the Atacama Desert, it was
B. rode on the crest of a tsunami (seismic sea wave), while it came to rest in the Atacama Desert,
C. rode on the crest of a tsunami (seismic sea wave) and came to rest in the Atacama Desert,
D. riding on the crest of a tsunami (seismic sea wave), to come to rest in the Atacama Desert
E. riding on the crest of a tsunami (seismic sea wave), it had come to rest in the Atacama Desert, which is
题目释义：On August.., the warship … rode on and came to…, some three miles up the….。
主语是the warship，谓语是rode on and came to ，some three miles up the coast and almost two miles inland from its initial anchorage是desert的同位语. anchored是过去分词,修饰the warship.
1868年8月13日, 战舰U. S. S. Wateree在Arica港口抛锚，该港口在智利北部的沿岸, 战舰遭遇海啸引发的浪潮，被冲至Atacama Desert。
考点：
平行对称，逻辑表达，题目释义
1. 一个完整的句子之中只能有一套主谓，当句子中有较长插入语时，要注意是否出现了两个主语，或没有连词连接的多个谓语动词的情况。
2. and引导的并列，通常要求词性、时态、单复数、逻辑等都要平行。
选项分析:
(A) coming与rode，anchored不平行；It was 多余造成两套主谓，run-on sentence
(B) while改变了原句逻辑意思，原意为”碰到海啸，并被刮到沙漠”，现改变为”当它在沙漠里休息的时候碰到了海啸”
(C) Correct，形式对称，逻辑正确
(D) riding，coming与anchored不平行，应统一用一般过去时；desert后面缺少逗号，使后面some three miles up the coast变成限定性修饰，改变原句合理逻辑含义
(E) 两套主谓，run-on sentence；riding与anchored不平行；had come没必要使用过去完成时态，破坏了其逻辑含义；which is可省略
168.
The first shots of the American Revolution, fired at Lexington and Concord, Massachusetts, were, according to legend, heard around the world, but news of these shots, which were sent by swift messenger, took four days in reaching New York City as well as another additional eleven days to reach Charleston, South Carolina.
A. shots, which were sent by swift messenger, took four days in reaching New York City as well as another additional eleven days
B. shots that was sent by swift messenger took four days in order to reach New York City, and also another eleven days
C. shots that were sent by swift messenger took four days to reach New York City and another eleven days
D. shots took four days by swift messenger in order to reach New York City and another eleven days in addition
E. shots took four days by swift messenger to reach New York City and another eleven days
题目释义：The first shots ... were … heard around the world, but news of these shots took four days by messenger to reach NYC and another eleven days to reach…
主语是The first shots，谓语hear, but做连词引导转折句，句子主语news ,谓语take，宾语four days/eleven days +不定式状语。
考点：
指代一致，逻辑表达，平行对称
1) as well as 与and 的意思不完全一致，作为习语用作介词时，as well as的涵义是“还有”、“不但…而且…”。值得注意的是，在A as well as B的结构里，语意的重点在 A，不在 B。因此，要注意句子想要表达的逻辑关系。
2) 句子结构，but连词，如果连接句子，则需要主谓结构齐全，因为连词连接的句子不一定主语相同，省略时可能不符合逻辑。
选项分析:
(A) Which were根据were说明which指代的是these shots，而逻辑上应该指代news，所以定语从句的谓语动词不是were应为was；没有take some days in doing sth的结构，且in reaching与后面的to形式不对称，应改为take some days to do sth.；as well as不用于同一层次并列。
(B) 用了限定性定语从句修饰news，意思成了是“信使所遣送的news”，错误，应该用非限定性修饰；in order to 在此应直接用to；also与another重复。
(C) 用了限定性定语从句修饰news错误同B；同时由于news是不可数名词，that were应改为that was。
(D) in order to 不简洁，可以直接用to；another和in addition语义重复。
(E) Correct；by swift messenger最为简洁。
补充说明：
关于限定性定语从句与非限定性定语从句 – by genimix
定语的限定与非限定并非是XDF和很多前人总结的那样是“局部”和“整体”的区别，这实际上是一种曲解
特别是不能绝对化的说：某个结构（介词短语）就一定是限定性，另一结构（现在分词）就一定是非限定性。
限定性与非限定性实质是：有该修饰时，修饰对象的外延是否有变化，如果变小了就是限定性，如果没变就是非限定性。
形式上简单的看，有没有逗号是明显标志。有逗号就是非限定性，没有逗号就是限定性。
实际上现在分词作定语如果没有逗号也是限定性，只是因为在GMAT中现在分词本身具有“客观状态”和“正在进行”意味，没有多种时态问题（这也正是现在分词完成式不做定语的原因），才使得其具有表达“重复多次性"意味的功能；而定语从句能够表达多种时态，因而倾向于表达”具体一次性“意味。
因此把限定性与非限定性说成是”局部“与”整体“的关系，不能说完全不对，但至少也是曲解了限定性与非限定性的本意
169. (GWD-3-Q11)
Retailers reported moderate gains in their November sales, as much because of their sales of a year earlier being so bad as that shoppers were getting a head start on buying their holiday gifts.
A. of their sales of a year earlier being so bad as that
B. of their sales a year earlier having been as bad as because
C. of their sales a year earlier being as bad as because
D. their sales a year earlier had been so bad as because
E. their sales of a year earlier were as bad as that
题目释义：Retailers reported …, as much because … as because ….. .
零售商报告其在11月销售温和上扬，一方面因为他们去年同期销售很糟糕，另一方面因为购物者都开始购买的节日礼物。
主语Retailer,谓语report, as much because … as because并列引导原因状语。过去完成时在这里使用是可以的，是在reported的过去，完成的事实。
考点：
平行对称
1. as much because …as because …，as …as 要求平行并列。
2. so bad可以单独使用做形容词，而as bad则后面必须再加比较成分，并不完整as bad as结构。
3. Shopper = customer 顾客，购物者
4. Head start = 抢先，提前
选项分析:
(A) as much…as…结构不平行；because of后面结构复杂，核心词只有their sales，应该改为because引导从句来清晰阐明原因。
(B) as much… as…结构不平行；as much… as bad as…搭配错误-- so bad是可以自己单独使用的，但是as bad的话后面必须再跟一个as；because of错误同A。
(C) as much… as…结构不平行；as much… as bad as…错误同B；because of错误同A。
(D) Correct；过去完成时以后面的were getting对照，说明a year earilier的sales发生在过去的过去；so bad不与后面的as搭配，而是前面的as much与as搭配
(E) 结构不平行, as much as和so bad,此处搭配混乱；第一个原因状语从句用过去完成时更贴切，因为第一个because是发生在去年，在第二个because之前，时态亦需要提前。
170. (GWD21-Q12)
Birds known as honeyguides exhibit a unique pattern of behavior: the bird leads another animal, such as a honey-badger or a human, to a bees’ nest with their chattering when they fly ahead; after the larger animal takes honey, the bird eats the wax and bee larvae.
A. with their chattering when they fly
B. with chattering and its flying
C. by chattering as it flies
D. by chattering and its flying
E. by chattering as they are flying
题目释义：the bird leads sth , , to a bees’ nest by chattering as it flies
主语是the bird，谓语动词lead sth to some place, by+分词结构为方式状语，as引导时间状语从句。
考点：
指代一致，逻辑表达
1. with和by的区别：
(1) 做某事时通过什么方法或手段用by：do something by (doing) something。
(2) 表示使用有形工具时，通常用with来表示：write with a pen, see with naked eyes, strike with a hammar
(3) 作”用”讲时，by和with的区别在于：with表示行为动作的工具，后面的名词一般要有冠词；by表示动作的手段，后面的名词一律不用冠词。
2. as和when引导的时间状语含义不同：
(1) as表示"当……时""一面……一面"，"随着"。具体用法如下：
1） 表示"当……时"、"和……同时"。常指从句的动作未结束，主句中的动作就已发生。从句中多用表示动作的动词，而不用be动词或表示感觉、理解、知道这类动词。
e.g. As he stood there, he saw two men enter the bar.
She dropped the glass as she stood up.
2） 用于平行的动作中，表示"一面……一面……"。常指一个主语同时进行两个动作。
e.g. The students took notes as they listened.
3） 用于平行发展的结构中，表示"随着……"。常指一个行为是另一个行为的结果，或一种状态随另一种状态变化。句中的动词多表示状态的发展变化。
e.g. As the wind rose the noise increased.
As it grew darker it became colder.
As he grew older he became more confident.
(2) when表示“当……的时候”。从句中既可用延续性动词，又可用非延续性动词，这些动词既可以表示动作，又可表示状态。从句中的动作既可和主句的动作同时发生，又可在主句的动作之前或之后发生。
When I came into the room, I found him lying there asleep. <表示动作，主从动作同时发生>
Mary was having dinner when I saw her. <表示动作，主从动作同时发生>
When you meet a word you don't know, consult the dictionary. <表示动作，从句动作在前>
She was beautiful when she was a girl. <表示状态>
*：所以，when引导的仅仅是最单纯的时间状语，在要表示伴随含义的时候，用as比用when更为合适。
选项分析:
(A) they以及their和前面未划线的the bird指代不一致，应为单数it；通过某某方法要用by，而不是with；when引导的时间状语从句没有伴随的含义，应该用as更好。
(B) 通过某某方式要用by，而不是with；chattering and its flying不平行；时间状语改为平行结构少了伴随、同时发生的含义。
(C) Correct，这里as是“一面飞一面喋喋”，上面谈到的as引导时间状语时的第2中用法。
(D) chattering and its flying不平行；时间状语改为平行结构少了伴随、同时发生的含义。
(E) the bird应为单数，指代词要用it。
