l's备考日记之SC错题+重点分析

lululuna

Word Selection
TIPS:
1)word selection要根据句意来，尤其是转折句，注意比较二者对比的是什么（babybearmm)
2)Parallelism 优先于 word selection (Ron)

*Althoughthey are crucially important, a person's total calorie intake is only one ofthe many factors that determine if their weight will increase or decrease.

A.they are crucially important, a person's total calorie intake is only one ofthe many factors that determine if their weight will increase or decrease

B. itis crucially important, a person's total calorie intake is only one of the manyfactors that determine whether his or her weight will increase or decrease

C. itis a crucially important factor, a person's total calorie intake is the onlyone of many that determines whether his or her weight will increase or decrease

D.crucially important, a person's total calorie intake is only one of the manyfactors that determines the increase or decrease in their weight

E. itis crucially important, a person's total calorie intake is the only one of manyfactors that determines the increase or decrease in his or her weight

*subjecy- pronoun
  A, they/thier  [size=13.9099998474121px]≠   a person's total calorie intake
  D，their [size=13.9099998474121px]≠ a person's total calorie intake

*determine
  +whether, 而不是if ，A out

*tricky about word selection between " determines" VS "determine"
babybearmm
source:http://forum.chasedream.com/thread-739174-1-1.html

1. “one of the many factors that determine” vs. “one of many factorsthat determines”
单复数，决定了后面that-clause描述的到底是”total calorie intake”这一个factor，还是”many factors”，而这又和全句的逻辑(“although”)密切联系。

2. 您可曾觉得 “determine whether sth will increase or decrease” 有些wordy, clumsy，而 ”determine the increase or decrease in sth” 很concise？If so, be careful! 这两者的意思是完全不同的！原句要说的是“决定是增加或是减少”，而E选项说的是“决定这个增加或减少的数值（量化）”。

Amixture of poems and short fiction, Jean Toomer’s Cane has been called one ofthe three best novels ever written by Black Americans—the others beingRichard Wright, author of Native Son, and Ralph Ellison, author of InvisibleMan

A.Black Americans—the others being RichardWright, author of Native Son, and Ralph Ellison, author of Invisible Man

B.Black Americans—including Native Son byRichard Wright and Invisible Man by Ralph Ellison

C. aBlack American—including Richard Wright,author of Native Son, and Ralph Ellison, author of Invisible Man

D. aBlack American—the others being RichardWright, author of Native Son, and Ralph Ellison, author of Invisible Man

E. aBlack American—the others being RichardWright’s Native Son and Ralph Ellison’s Invisible Ma

OA:E

don't split on word choice first. that'snot a smart way to split.

*go with grammar first.
in this case, parallel structure is pretty easy. the sentencemakes it clear that you're comparingnovels, not their authors, so (a),(c), and (d) are instantly out because their second halves mistakenlymention the people themselves as part of the comparison.
(b) is not as parallel as (e), either. since the originalsays "jean toomer's cane", the others should alsohave the form "X's Y", not "Y by X".

--

*word choice is a sticky thing. for instance,it's actually better to say "birds have a four-chamberedheart" than to say "birds have four-chambered hearts", because the formermakes it clear that each bird has exactly 1 heart. both, however, areacceptable.
in a similar vein, the construction of (d) and (e)makes it more clear that each book has exactly 1 author.

remember - don't question correct answers; learnfrom them.

--

*NEVER split on word choice before parallelism(which is possibly the single most important topic in SC). that's arecipe for disaster.

--

lululuna

词的位置

7/18
GWD-31-Q30

The United States petroleum industry’s cost to meet environmentalregulations is projected at ten percent of the price per barrel of refinedpetroleum by the end of the decade

A.    The United States petroleum industry’s cost to meet environmentalregulations is projected at ten percent of the price per barrel of refinedpetroleum by the end of the decade.  

B.     It is estimated that by the end of the decade the cost to the UnitedStates petroleum industry of meeting environmental regulations will be tenpercent of the price per barrel of refined petroleum.

C.    By the end of the decade, the United States petroleum industry’scost of meeting environmental regulations is projected at ten percent of theprice per barrel of refined petroleum.   

D.    To meet environmental regulations, the cost to the United Statespetroleum industry is estimated at ten percent of the price per barrel ofrefined petroleum by the end of the decade.   

E.     The United States petroleum industry’s cost by the end of the decade to meetenvironmental regulations is estimated at ten percent of the price per barrelof refined petroleum.   

OA: B

7/19

GWD_22_Q33P-28

The spectacular disintegrationof a comet last year in full view of ground- and space-based telescopesprovided new insights into how comets form and may thus forcea rethinking of the role of comets in the delivery of organic compounds to theevolving Earth.

A.   The spectaculardisintegration of a comet last year in full view of ground- and space-basedtelescopes provided new insights into how comets form and may thus force

B.    The spectacular disintegrationof a comet last year in full view of ground- as well asspace-based telescopes, provided new insightsinto how comets form and thus possibly forcing

C.   When a comet'sspectacular disintegration occurred in full view of ground- and space-basedtelescopes last year, it provided new insightsinto how comets form and thus may possibly force

D.   Last year, in full view ofground- and space-based telescopes, a comet's spectacular disintegration provided new insights into how comets form and thus possibly forcing

E.    Last year, in full view ofground- as well as space-based telescopes, thespectacular disintegration of a comet has provided new insights into how cometsform and may thus force

OA: A

*and VS as well as
  and -并列
  as well as-次级并列，不可互换；
  A/E out

*possible  VS may
=> redundancy 永远错

*介词短语的位置
last year 修饰 spectacular disintegration,
in full view of ……也修饰spectacular disintegration
是指 去年的通过地面望远镜和太空望远镜全景看到的壮观的彗星瓦解
  
D/E把介词拖到主句外，改变了句意，last year修饰整句

A.    The spectacular disintegration of a comet last year in full view of ground- and space-based telescopes provided new insights into how comets form and may thus force

B.     The spectacular disintegration of a comet last year in full view of ground- as well as space-based telescopes, provided new insights into how comets form and thus possibly forcing

C.    When a comet's spectacular disintegration occurred in full view of ground- and space-based telescopes last year, it provided new insights into how comets form and thus may possibly force

D.    Last year, in full view of ground- and space-based telescopes, a comet's spectacular disintegration provided new insights into how comets form and thus possibly forcing

E.     Last year, in full view of ground- as well as space-based telescopes, the spectacular disintegration of a comet has provided new insights into how comets form and may thus force

lululuna

7/20错题

GWD30-Q17:待解决

By the same techniques used for genetically enhancing plants, making themdisease- or pest-resistant, researchers have been able to increase the amountof protein in potatoes, sweet potatoes, and tobacco.

A.    Bythe same techniques used for genetically enhancing plants, making them

B.     Withthe same techniques to genetically enhance plants, so that they are      

C.    Employingthe same techniques used to genetically enhance plants so that they are

D.    Employingthe same techniques to genetically enhance plants, which makes them

E.     Employingthe same techniques for genetically enhancing plants that make them

1）meaning
两层：
（1）方法  使得 植物抗虫抗病
       说的是方法的功能，区别to do 和 for doing 用法的区别在于本帖9#

my thought on this, based on the examples you provide, is that "to do" would modify a verb and "for doing" would modify a noun:

I bought a lawnmower to mow my lawn. (that's why I bought it)

I bought a lawnmower for mowing my lawn. (that's what it's used for)

（2）采用这个方法， 研究人员能产出蛋白质含量高的西红柿、甜西红柿和烟草 => A/B out

*A，“making them……" 根据句意指向采用方法，但是放在researchers前面有两头修饰的可能性；无法精确表达 "采用这个方法后使得这些植物……"；

            used for 是错的，应该是to
       B,  with无法采用通过方式，不如employing好，同事they指代有问题
       C，
       D，WHICH=>PLANT,且 WHICH不能指代前面整句
       E，

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GWD-29-Q39

Scientists have recently discovered that the ultrathin, layered construction of abutterfly’s wings, the same as the one making some butterflies shimmer viathe phenomenon of iridescence, are enabling the insect to control how muchheat energy is absorbed by its wings and how much is reflected away.

A.    wings,the same as the one making some butterflies shimmer via the phenomenon ofiridescence, are enabling

B.     wings,which is the same one that makes some butterflies shimmer via the phenomenon ofiridescence, that also enables

C.    wingsis the same as the one that makes some butterflies shimmer via the phenomenonof iridescence, enabling

D.    wings—thesame construction that makes some butterflies shimmer via the phenomenon ofiridescence—also enables

E.     wings—ofthe same construction that makes some butterflies shimmer via the phenomenon ofiridescence—also enable

OA： D
Meaning
1）科学家发现 U=> enables
2）construction of b wings-the same construction……-,补充修饰contruction

lululuna

7/21错题

GWD23_Q32: PP61.

Amonglower-paid workers, union members are less likely than nonunion members to beenrolled in lower-end insurance plans imposing stricter limits on medicalservices and requiring doctors to see more patients, and spend less timewith each.

A.   imposing stricter limits on medical services andrequiring doctors to see more patients, and spend

B.     imposingstricter limits on medical services, requiring doctors to see more patients,and spending

C.    that imposestricter limits on medical services, require doctors to see more patients, andspend

D.    that imposestricter limits on medical services and require doctors to see more patients,spending

E.     that imposestricter limits on medical services, requiring doctors to see more patients andspending

D

一万遍！！Meanning,越做到后面越要细致，不要秒选。。。。

Q39: PP64

Whereas theuse of synthetic fertilizers has greatly expanded agricultural productivity inmany parts of the world, an increase in their use can create seriousenvironmental problems such as water pollution, and their substitution for moretraditional fertilizers may accelerate soil structure deterioration andsoil erosion.

A.    an increase intheir use can create serious environmental problems such as water pollution,and their substitution for more traditional fertilizers

B.     an increase intheir use can create serious environmental problemslike water pollution, and if substituted for more traditionalfertilizers, it

C.    if thesefertilizers are used increasingly, they cancreate serious environmental problems such as water pollution, and if used assubstitutions for more traditional fertilizers, they

D.    the increasedusage of these fertilizers can create serious environmental problems such aswater pollution, while if substituted for more traditional fertilizers, this substitution

E.     the increasedusage of these fertilizers can create serious environmental problems like water pollution, while their substitution formore traditional fertilizers

OA: A

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Q40: PP65

A decade after initiating the nation's most comprehensive andaggressive antismoking program, per capita consumption of cigarettes inCalifornia declined from over 125 packs annually per person to about 60, a dropmore than twice as great as in the nation as a whole.

A.   per capita consumption of cigarettesin California declined from over 125 packs annually per person to about 60, adrop more than twice as great as

B.     annualper capita consumption of cigarettes in California declined from over 125packs to about 60, more than twice as great as that

C.    California'sannual per capita consumption of cigarettes declined from over 125 packs perperson to about 60, more than twice as great as the drop

D.    California hasseen per capita consumption of cigarettes decline from over 125 packs annuallyto about 60, a drop more than twiceas great as that

E.     California hasseen annual per capita consumption of cigarettesdecline from over 125 packs per person to about60, more than twice as great as that

OA: C

lululuna

OG16_37

Not trusting themselves tochoose wisely among the wide array of investment opportunities on the market, stockbrokersare helping many people who turn to them to buy stocks that could be easilybought directly.

(A) stockbrokers are helpingmany people who turn to them to buy stocks that could be easily

(B) stockbrokers are helpingmany people who are turning to them for help in buying stocks that they could easilyhave

(C) many people are turningto stockbrokers for help from them to buy stocks that could be easily

(D) many people are turningto stockbrokers for help to buy stocks that easily could have been

(E) many people are turningto stockbrokers for help in buying stocks that could easily be

*openning modifier
   A/B out
*in doing VS to do

dukb24 语法课

in doing vs. to do

“subject + clause + in verbing”, subject + clause 一定要作为verbing这个action的一部分。=>结合下面OG解释

E.g. I solved all the problems in PREP in preparing for the GMAT.

to do表示目的→ I buy a shoe to run.

OG:  Logical predication; Grammaticalconstruction; Verb form

Thissentence is intended to be about people who, because they do not trust themselvesto make wise investment decisions, turn to stockbrokers for advice. As the sentenceis worded, however, it is stockbrokers who do not trust themselves to choose wisely.The sentence is made even more incomprehensible by the peculiar placement of theadverbs in the phrase, could be easily bought directly.

D.To buy is not idiomatic in this context—in buyingwould be correct—and the tense of the verb could have been does not match the tenseof the verb earlier in the clause; the point is not that people are turning to stockbrokersfor help in buying stocks that at some earlier time could have been bought directly,but rather that the stocks could be bought by the people directly at the very timethey are seeking help from the stockbrokers.

E. Correct. The opening clause correctly modifiesmany people, and the adverb is correctly placed. The correct answer

联想～OG16 Diagnostic Test#36题

New data from United States Forest Service ecologists show that for every dollar spent on controlled small-scale burning, forest thinning, and the

training of fire management personnel, it saves seven dollars that would not be spent on having to extinguish big fires.

(A) that for every dollar spent on controlled small-scale burning, forest thinning, and the training of fire management personnel, it saves seven dollars

that would not be spent on having to extinguish

(B) that for every dollar spent on controlled small- scale burning, forest thinning, and the training of fire- management personnel, seven dollars are saved

that would have been spent on extinguishing  

(C) that for every dollar spent on controlled small- scale burning, forest thinning, and the training of fire- management personnel saves seven dollars on

not having to extinguish

(D) for every dollar spent on controlled small- scale burning, forest thinning, and the training of fire- management personnel, that it saves seven dollars

on not having to extinguish

(E) for every dollar spent on controlled small- scale burning, forest thinning, and the training of fire- management personnel, that seven dollars are saved

that would not have been spent on extinguishing

OA: B

A: pronoun error（it没有指代对象)；would not be spent使用错误;;

C: sentence fragment;;

D: sentence fragment;;

E: sentence fragment;;

lululuna

Modifier的逻辑顺序和位置

OG16_63.

Having been named for a mythological nymph who cared for the infant Jupiter, the asteroid named Ida, in the middle of the belt of asteroids that

orbit the Sun between Mars and Jupiter, was discovered in 1884.

(A) Having been named for a mythological nymph who cared for the infant Jupiter, the asteroid named Ida, in the middle of the belt of asteroids that

orbit the Sun between Mars and Jupiter, was discovered in 1884.

(B) Discovered in 1884, the asteroid Ida, named for a mythological nymph who cared for the infant Jupiter, is in the middle of the belt of asteroids that

orbit the Sun between Mars and Jupiter.

(C) In the middle of the belt of asteroids that orbit the Sun between Mars and Jupiter, the asteroid Ida, discovered in 1884 and named for a

mythological nymph who cared for the infant Jupiter.

(D) The asteroid Ida, named for a mythological nymph who cared for the infant Jupiter and discovered in 1884, is in the middle of the belt of asteroids

to orbit the Sun between Mars and Jupiter.

(E) Ida, an asteroid discovered in 1884 and which was named for a mythological nymph who cared for the infant Jupiter, is in the middle of the belt of

asteroids to orbit the Sun between Mars and Jupiter

DUKB24

在使用VING/VED/ADJ这一类的modifier的时候，一定要去注意检查modifier的放置的顺序是否合理。

确保放在前面的modifier能lead to or result in 后面

句子的信息。

E.g.

Slipping on the ice, Tom broke his ankle. （√）

Breaking his ankle, Tom slipped on the ice （X）

A: modifier placement error；

C：sentence fragment；

D：incorrect parallelism；sentence meaning；

E：incorrect parallelism；sentence meaning；

OG_explaination

Rhetorical construction;Logical predication; Grammatical construction

Thissentence describes a discovery that occurred in 1884 and provides some additionalinformation about the object that was discovered. The most effectively worded answerchoice opens with a past‐participial phrase(discovered . . .) describing the subject of the sentence, the asteroid Ida. Ida’sdiscovery is logically prior to its naming, described in a second past, followingthe subject (named . . .). The sentence is then completed with a present tense linkingverb is + prepositional phrase to explain Ida’s location.

A，Opening with a past perfect passive verb, Having been named, this version of thesentence illogically suggests that being named for a mythological nymph precededthe discovery of Ida.

B，Correct. This version is clear, logically coherent, and grammatically correct.

C，This version of the sentence is ungrammatical; it has no main verb for the subjectthe asteroid Ida.

D，The sequence of events is obscured by the placement of named before discovered inthe compound participial phrases. The infinitive form to orbit is ungrammaticalin place of the relative clause.

E，This sentence awkwardly attempts to use a compound conjunction and to join the pastparticipial phrase discovered in 1884 with the relative clause which was named.. . . The infinitive form to orbit is ungrammatical in place of the relative clause.

Thecorrect answer is B.

联想：PREP07 PART1#110题

The federal immigration station on Ellis Island, which was first opened in 1892, then rebuilt in 1900, processing nearly three quarters of all immigrants

entering the United States in the first quarter of the twentieth century.

(A) The federal immigration station on Ellis Island, which was first opened in 1892, then rebuilt in 1900, processing nearly three quarters of all

immigrants entering the United States in the first quarter of the twentieth century.

(B) Having processed nearly three quarters of all immigrants who enter the United States in the first quarter of the twentieth century, the federal

immigration station on Ellis Island first opened in 1892 and then was rebuilt in 1900.

(C) Processing nearly three quarters of all immigrants to enter the United States in the first quarter of the twentieth century, the federal immigration

station on Ellis Island first opened in 1892, being rebuilt in 1900.

(D) First opened in 1892, then rebuilt in 1900, the federal immigration station on Ellis Island processed nearly three quarters of all immigrants entering

the United States in the first quarter of the twentieth century.

(E) Of all immigrants to enter the United States in the first quarter of the twentieth century, the federal immigration station on Ellis Island processed

nearly three quarters of them, having first opened in 1892 and rebuilt in 1900.

OA: D

A: sentence fragment

B：modifier placement error；

C：modifier placement error；

E：modifier error（having first opened…和前面句子不是修饰关系）；

redundancy (of al …. & of them)

lululuna

7/22
T-9-Q39

Studies showthat young people with higher-than-averageblood pressure and their families have a historyof high blood pressure are more likely than others to develop a severe formof the condition.

A.     and theirfamilies have a history of high blood pressure  

B.      whose families have a history ofhigh blood pressure

C.       and a history of high blood pressure runsin the family  

D.     whose families have a history ofhigh blood pressure

       E.      with a history of high blood pressure running in their family

OA: B
but/and 连词，采用lock-in-word法，找前面对应的词，有且只有一个才可准确平行；

T-9-Q29

Several studies have foundthat the coronary patients who exercise most actively have half or less thanhalf the chance of dying of a heart attack as those who are sedentary.

A.   have half or less than half the chance ofdying of a heart attack as those who aresedentary  

B.   have half the chance,or less, of dying of a heart attack thanthose who are sedentary do  

C.   have half the chance that they will die of aheart attack, or less, than those who aresedentary do

D.   are at least fifty percent less likely to die of a heart attack as those who are sedentary

E.    areat least fifty percent less likely than those who are sedentary to die of aheart attack

OA:E

lululuna

OG13_Round2_最后刷，未完全掌握须mark的知识点

5.Of  all the vast tides of migration that have swept through  history, maybe none is  more concentrated as the wave that brought 12  million immigrants onto American shores in little more than three  decades.      (A) maybe none is more concentrated as   (B) it may be that none is more concentrated as   (C) perhaps it is none that is more  concentrated than   (D) maybe it is none that was more concentrated than   (E)  perhaps none was more concentrated than OG： *TENSE In addition, the  second part of the sentence uses the past tense verb brought, indicating that  the event is over. The verb used in the comparative construction must also be  past tense, x (none) was more concentrated than y (the wave).    *强调句 VS 陈述句   C， It is none that is more …is wordy; also, in this context, it must refer to something (unlike in  phrases such as “it is clear that ……”), yet it          does not plausibly refer to  anything.   D， As in (C), it is none that was more . . . is wordy; it must refer to  something, yet it does not plausibly refer to anything. DUKB24_og13千行 *强调句不符合句意，因为句意是比较个体和群体 个体“ wave that brought 12  million……”； 群体" all the vast tides of migration that……“； 而不是强调某一个tidal,所以强调句改变了歧义

OG13_30

Paleontologists believe that fragments of a primate jawbone unearthed in Burma and estimated at 40 to 44 million years old provide evidence of a crucial step along the evolutionary path that led to human beings.

(A) at 40 to 44 million years old provide evidence of
(B) as being 40 to 44 million years old provides evidence of
(C) that it is 40 to 44 million years old provides evidence of what was
(D) to be 40 to 44 million years old provide evidence of
(E) as 40 to 44 million years old provides evidence of what was
oa: D

idiom:
be estimated to be !!!!!!!!!!!!
不是at

39. Although schistosomiasis is not often fatal, it is so debilitating that it has become an economic drain on many developing countries.
(A) it is so debilitating that it has become an economic
(B) it is of such debilitation, it has become an economical
(C) so debilitating is it as to become an economic
(D) such is its debilitation, it becomes an economical
(E) there is so much debilitation that it has become an economical

in general, you don't use so ADJ as to VERB unless the VERB describes some sort of state/condition. i.e., if the verb is an action verb, this construction generally isn't used.

for instance,
i am so ugly as to be viscerally repulsive to women. --> this works, because the verb “to be” describes a state/condition.
i am so ugly as to repel women on sight. --> you generally wouldn't see this in good writing, as “repel” is an action verb; the sentence would probably be written as i am so ugly that i repel women on sight.

og13_76

Combining enormous physical strength with higher intelligence, the Neanderthals appear as equipped for facing any obstacle the environment could put in their path, but their relatively sudden disappearance during the Paleolithic era indicates that an inability to adapt to some environmental change led to their extinction.

(A) appear as equipped for facing any obstacle the environment could put in their path,

(B) appear to have been equipped to face any obstacle the environment could put in their path,

(C) appear as equipped to face any obstacle the environment could put in their paths,

(D) appeared as equipped to face any obstacle the environment could put in their paths,

(E) appeared to have been equipped for facing any obstacle the environment could put in their path,

OA: b

Verb  form; Diction

Because Neanderthals “disappeared,” the verb describing their apparent abilities cannot be present tense, so as equipped must be changed to to have been equipped. The expression equipped to face is clearer and more direct than  equipped for facing.

A As equipped indicates that Neanderthals still appear this way; equipped should be followed by an infinitive form  instead of  a  prepositional phrase.

B Correct. The verb tense clearly indicates that the current evidence is about Neanderthals in the past.

C  As equipped does not indicate that Neanderthals appeared this way  in  the past;  while  individual

Neanderthals may well have followed different paths, this sentence is about the single evolutionary path taken by  Neanderthals as a species.

D Present-tense appear is needed to parallel present-tense indicates and to reinforce that this is current evidence about Neanderthals in  the past;  as in  (C), paths should be singular.

E For facing is an incorrect substitution  of a  prepositional phrase for an   infinitive.

!!!!excellent explanation on tense issue

tense problem is not mainly grammer problem;
it's more about meaning of the sentence.

句意：

The N appear to have been…… , but their disappearance indicates that……

两个分句都是在讲N这个人，现在看来 当时是准备好面对任何困难的， 但是他们的消失 现在 表明他们并不能适应那些导致他们灭绝的环境。

OG13_76

A 1972 agreement between Canada and the United States reduced the amount of phosphates that municipalities had been allowed to dump into the Great Lakes.

(A) reduced the amount of phosphates that municipalities had been allowed to dump

(B) reduced the phosphate amount that municipalities had been dumping

(C) reduces the phosphate amount municipalities have been allowed to dump

(D) reduced the amount of phosphates that municipalities are allowed to dump

(E) reduces the amount of phosphates allowed for dumping by municipalities

OA: D

Verb  form; Idiom

An agreement that occurred in 1972 is correctly described with the past tense verb reduced. Since the dumping continued after the date of the agreement, the past perfect verb had been allowed should instead be the present are allowed (if the agreement remained in effect when the sentence was written) or the past were allowed (if the agreement was no longer in effect when the sentence was written).Since were allowed does not appear in any of the options, we can assume that the correct verb tense is are allowed. The phrase amount of phosphates is clear and idiomatically  correct, whereas phosphate  amount is not  idiomatic.

A The past perfect tense indicates that the condition referred to was no longer in effect at the time of the agreement. The agreement could not have retroactively changed what was no longer in existence. The sentence refers to a continuing (but modified) prescription as to the allowable amount, not to an amount that is actually dumped. Thus, it is preferable to use either the simple past tense or the timeless present tense.

B The phosphate amount should be the amount of phosphates; the omission of some form of allow is incorrect since the agreement changed not the amount dumped, but the amount permitted to be dumped.

C Present tense reduces should be the past tense reduced; the phosphate amount should be the amount of phosphates;  have been  allowed should be are  allowed.

D Correct. The past tense reduced is correctly used in this sentence to describe a past action, and the present tense are allowed is used to describe the continuing applicability of the modified rule or regulation.

E Present tense reduces should be the past tense reduced; allowed for dumping is an incorrect idiom; allowed for  dumping by  municipalities is awkward.

By Ron:"

1,Reduce" is not an ongoing state of existence. It's something that happens at one particular point in time.
That point in time was in 1972. So, past tense.
Analogy: I lost a bunch of weight in 2010. I can't write "I lose weight" now... because it happened in 2010.
Reduced, lost, same idea.

2,You have to read those choices literally.
"The amount they had been allowed to dump", and/or "...had been dumping", are historical figures. They're a done deal; they can't be changed.

If this still doesn't make sense to you, put a (pre-1972) year on them. E.g., the amounts that were specified in 1969.
Perhaps that will make it more clear"”you can't reduce the amounts that were specified in 1969, because they were specified in 1969. (The current figure can represent a diminution from those historical figures, but a diminution of those figures is impossible; we can't change history.)

lululuna

7/25
Through VS  BY
by强调动作，与主句动作发出为同一主体；
through强调方式方法，加名词；


PREP
The Chicago and Calumet Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been redirected by constructing canals so that the water now empties into the Mississippi by way of the Illinois River.

A，Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been redirected by constructing  
B，Rivers had originally flowed into the St. Lawrence by way of Lake Michigan, but they have been redirected by constructing  
C，Rivers, which originally flowed into the St. Lawrence by way of Lake Michigan but have been redirected by the construction of  
D，Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, but having been redirected by the construction of  
E，Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of

OA: E

A，but前后不平行，错
C， sentence fragment
D,   but 前面没句子，sentence fragment

Narrow to B/E
B, 1) past perfect tense 没有时间标志；
    2)后半句 they ……by construciting, 动作发出者指向they(rivers)歧义
E, through 通过……途径/方法

Ron:https://www.manhattanprep.com/gmat/forums/the-chicago-and-calumet-rivers-originally-flowed-into-the-t3836.html?hilit=The%20Chicago%20and%20Calumet%20Rivers%20originally%20flowed%20into%20the%20St.%20Lawrence%20by%20way%20of%20Lake%20Michigan,%20but%20having%20been%20redirected%20by%20co

there are two things wrong with (b).

one:
the use of the past perfect (had flowed) is inappropriate, because there is no second past-time marker or event to which this first event is relevant.
compare: the rivers had originally flowed into the st. lawrence, but then their course was divertedby...
the correct tense to use here would be the simple past, because this is the only past time frame referenced in the whole sentence.

two:
'by constructing' seems to refer back to the rivers as its ostensible subject, implying (absurdly) thatthe rivers themselves constructed the canals.

PREP7_SC_82.
Each year companies in the United States could save as much as $58 billion annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided offices with cleaner air.

(A) annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided
(B) annually if they prevented employee illness and gain as much as $200 billion through worker performance improved by simply providing
(C) annually in employee illness prevention and gain as much as $200 billion through worker performance improved by simply providing
(D) in employee illness prevention and gain as much as $200 billion through improving performance of workers if they simply provided
(E) by preventing illness among employees and gain as much as $200 billion through improved worker performance if they simply provided

OA: e

lululuna

7/26

T-4-Q1

Scientists have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia to between 2.52 and 2.60 million years ago, pushing back by more than 150,000 years the earliest date when it is known that humans made stone tools.

A. when it is known that humans made

B. at which it is known that humans had made

C. at which humans are known to have made

D. that humans are known to be making

E. of humans who were known to make

OA: C

in this sort of construction, i'm pretty sure that either "when" or "at which" would be acceptable. (clearly, the latter is acceptable -- it appears in the correct answer, after all -- but i wouldn't object to the former.)
if you want to get really subtle, i think (not 100% sure) that "the date when" is used for actual, precise calendar dates, whereas "the date at which" is used for the usually more vague dates ofhistorical events, such as the one in this problem. but i'm sure the test is not going to depend on this sort of nuanced difference.

i think the real problem with the construction in choice (a) is that the clause following "when" is "it is known". in other words, that choice suggests that the fact is (was?) known at that date, an interpretation that clearly doesn't make sense in context.in the correct answer, the "at which" is followed by a clause whose subject is "humans", and which describes the actual action that took place at that date. therefore, i think the idea is that this clause more accurately describes the chronology of the events: i.e., the toolmaking happened at that date, and the fact is known now.

as for your other question, this isn't really a perfect tense, because it's actually not a tense at all -- it's an infinitive.
probably the easiest way to go here is to remember this as an idiomatic usage of the construction "known to". if the action is in the present, then you use "known to VERB"; if the action is in the past, then you use "known to have VERBed". as far as i know, these are the only two possible forms.

T-4-Q12

For the farmer who takes care to keep themcool, providing them with high-energy feed, and milking them regularly,Holstein cows are producing an average of 2,275 gallons of milk each peryear.

A.   providing them with high-energyfeed, and milking them regularly, Holstein cows are producing

B.    providing them with high-energyfeed, and milked regularly, the Holstein cow produces

C.   provided with high-energy feed,and milking them regularly, Holstein cows are producing

D.   provided with high-energy feed,and milked regularly, the Holstein cow produces

E.    provided with high-energy feed,and milked regularly, Holstein cows will produce

OA: E

heh. it looks like choice (a) is an"indian trap"
seriously, not a joke.
if there is a single biggest issue in the grammar of second-languageenglish speakers who happento hail from india or pakistan, thatissue is the drastic overuse of the "are ...ing"construction. (native speakers of english will recognize "areproducing" at once as awkward.)

another problem with part (a) is the modifier. although"providing... and milking..." is agrammatically acceptablemodifier, it doesn't make any sense in context, since these are not two thingsthat farmers do WHILE or AS A CONSEQUENCE OF keeping the cows cool.(if you're going touse comma + -ing, then one of these two should hold.)
see #124 (og 12th edition) or #127 (og 11th edition), correct answer, for asentence in which such a modifier actually does make sense.

T-4-Q39

Five hundred million different species ofliving creatures have appeared on Earth, nearly 99 percent of them vanishing.

A.   Five hundred million differentspecies of living creatures have appeared on Earth, nearly 99 percent of them vanishing.

B.    Nearly 99 percent of five hundred milliondifferent species of living creatures that appeared on Earth have vanished.

C.   Vanished are nearly 99percentof the five hundred million different species of living creatures that appearedon Earth.

D.   Of five hundred milliondifferent species of living creatures that have appeared on Earth, nearly 99percent of them have vanished.

E.    Of the five hundred milliondifferent species of living creatures that have appeared on Earth, nearly 99percent have vanished.

oa:e

STACY manhattan

B has a verb tense issue. It says "species that appeared" on earth. Appeared is simple past but, in this case, we want present perfect. We use past tense to discuss something that is completely over; we use present perfect to discuss something that started in the past but is either still true or still going on in the present. It is still true that the species appeared, so we want to say "have appeared"