I can’t complain about this one. “Carbon dioxide gas” is a singular, non-countable noun, so “less” works fine as a modifier. And this part is a little bit tricky, but the second part of the sentence refers to several different “gasses” – a countable, plural noun – so “fewer” is appropriate.

The phrase beginning with “that” (“that have been implicated…”) correctly modifies “other gasses.” It’s also completely fine to use the “-ing” form of the verb after “as well as.”

So I guess we’ll keep (A).


It’s a funny quirk of English: if “as well as” were changed to “and” then we’d want the verbs “burn” and “emit” to be in parallel form. But since we have “as well as”, we’re better off using “emitting”, as we did in (A).

More importantly, I can’t make any sense of the “having been” at the end of the underlined portion. For that reason, we can scrap (B).


You could argue that the pronoun “they” is ambiguous here, since it could refer to “diesel engines” or “gasoline engines”, but I’m not convinced: since “they” is the subject of the second clause, it can generally refer back to the subject of the first clause on the GMAT without causing any trouble.

But we definitely have a modifier problem here: “fewer carbon dioxide” doesn’t make any sense, since “carbon dioxide” is a non-countable noun, and “fewer” can only be used with countable nouns. (If you’re not clear about that concept, try counting the noun out loud: “one carbon dioxide, two carbon dioxides, three carbon dioxides…” That makes no sense at all, right? So “carbon dioxide” is non-countable.)

So (C) is gone.


The first part of the underlined portion isn’t necessarily WRONG, but it definitely isn’t great: “gasoline engines that have a comparable size” is a really crappy way to say “gasoline engines of comparable size.” I just don’t think it makes sense to use the word “have” in this context, since gasoline engines don’t really possess size.

More importantly, we have a problem with the non-countable modifier “less”, since it seems to be modifying both “carbon dioxide gas” (non-countable) and “other gasses” (countable) – and “less” can’t modify a countable noun.

So (D) is out, too.


The first part of the underlined portion suffers from the same problem as (D): “that have a comparable size” is a lousy way to say “of comparable size.” But again, I wouldn’t necessarily eliminate (E) based on that issue by itself.

The other problem is the same as in (D): “less” seems to modify “other gasses”, and that doesn’t work. Plus, I’m really not sold on the idea of using “having” to modify “gasses” at the end of the underlined portion – the version in (A) (“gasses that have…”) seems a little bit better.

In any case, (E) can be eliminated, and we’re left with (A).
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Ds burn less fuel than Gs of comparable size (preferable to "that have a comparable size" )

"far less carbon dioxide gas" is correct, not "far fewer carbon dioxide gas". Carbon dioxide gas is uncountable and needs "less", not "fewer". (C) is out.

"far fewer of the other gasses" is correct since other gasses are countable other gasses. But you must mention carbon dioxide first to say something about "other" gases. So (D) and (E) are out.

"other gasses having been implicated" is incorrect. We need to write "other gasses that have been implicated".
"having been implicated" means they were implicated in the past but are not now. That doesn't make sense. The other gasses are still implicated. (B) is out.

(A) is fine. "and" needs parallel elements, but "as well as" does not. Hence "emitting" is not a problem.
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Meaning: Compared to gasoline engines of comparable size, diesel engines burn up to 30 percent less gas than gasoline engines burn. In addition, diesel engines emit far less carbon dioxide and other greenhouse gases [than gasoline engines of comparable size emit]. These gases have been determined [identified] as contributors to global warming.

• Split #1: less . . . THAN

Correct: Diesel engines burn as much as 30 percent less fuel THAN . . . gasoline engines do.
Options A and B incorrectly say less . . . AS
Eliminate Options A and B

• Split #2: Parallelism

Correct: Diesel engines burn . . . and emit . . .

Option D incorrectly says Diesel engines burn . . . and emitting. . .
Eliminate Option D

• Split #3: Meaning

Three of these options convey the wrong or very unclear meaning.

Option E states: gasoline engines whose size is comparable? Don't let your mind fill in the details.
There's nothing to compare the size to. The size is comparable to what, exactly?
Eliminate E

Option D (already eliminated) says, "gases, which have been determined as contributors." The gases are stubborn or resolute contributors to global warming? No.
(I have been determined to find information about XYZ = I have been stubborn and persistent in my search for information about XYZ.)

Stubborn and resolute are synonyms for determined, a meaning that (D) erroneously suggests and that is different from identified [as].

Option B (already eliminated) says, "they [engines] have determined to contribute." That clause implies that the engines have decided to contribute to global warming.

The answer is C
• less . . . than is correct
• engines OF comparable size conveys the correct meaning
• gases, which have been determined as contributors correctly indicates that the gases have been identified as contributors

OTHER ISSUES
• Phrasing

The correct phrasing is determined to contribute. Options A, D, and E use different and incorrect phrasing.

Finally, Option A says "engines with comparable size." Not correct.
Correct: engines [that are] OF comparable size.
An engine (or any thing) is not with a size.

C is correct. I hope that helps.
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Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have been implicated in global warming.

(A) of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have Correct answer and no apparent errors.

(B) of comparable size, as well as emit far less carbon dioxide gas and far fewer of the other gasses having "having been" must be used to denote an action that has happened before another action. Incorrect usage here. Eliminate.

(C) of comparable size, and also they emit far fewer carbon dioxide and other gasses that have "and also" and "they" are redundant. Also, "far fewer carbon dioxide" is incorrect - need to use "lesser" for an uncountable. Eliminate.

(D) that have a comparable size, and also they emit far fewer of the other gasses having Omits to mention "carbon dioxide". "and also" and "they" are redundant. "having been" must be used to denote an action that has happened before another action. Incorrect usage here. Eliminate.

(E) that have a comparable size, as well as emitting far fewer of the other gasses having Omits to mention "carbon dioxide". Also, "having been" must be used to denote an action that has happened before another action. Incorrect usage here. Eliminate.

Hope this helps.
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Dear Friends,

Here is a detailed explanation to this question-

Concepts tested here: Verb Forms + Idioms + Awkwardness/Redundancy

• The present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.
• “few”/”a few” are exclusively used to refer to plural nouns and countable nouns, and “less”/”a little” are exclusively used to refer to singular nouns and uncountable nouns; “any”, “none”, “all”, and “some” can be used to refer to plural and uncountable nouns and singular and countable nouns.

A: Correct. This answer choice correctly uses the present perfect tense verb "have been implicated" to refer to an action that concluded in the past but continues to affect the present. Further, Option A correctly uses "less" to refer to the uncountable noun "carbon dioxide" and "fewer" to refer to the countable noun "gasses". Additionally, Option A is free of any awkwardness or redundancy.

B: This answer choice incorrectly uses the participle construction "having been implemented" to refer to an action that concluded in the past but continues to affect the present; remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.

C: This answer choice incorrectly uses "fewer" to refer to the uncountable noun "carbon dioxide"; remember, “less”/”a little” are exclusively used to refer to singular nouns and uncountable nouns, and “few”/”a few” are exclusively used to refer to plural nouns and countable nouns.

D: This answer choice incorrectly uses "less" to refer to the countable noun "gasses"; remember, “few”/”a few” are exclusively used to refer to plural nouns and countable nouns, and “less”/”a little” are exclusively used to refer to singular nouns and uncountable nouns. Further, Option D uses the needlessly wordy phrase "that have a comparable size", leading to awkwardness and redundancy.

E: This answer choice incorrectly uses the participle construction "having been implemented" to refer to an action that concluded in the past but continues to affect the present; remember, the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present. Further, Option E incorrectly uses "less" to refer to the countable noun "gasses"; remember, “few”/”a few” are exclusively used to refer to plural nouns and countable nouns, and “less”/”a little” are exclusively used to refer to singular nouns and uncountable nouns. Additionally, Option E uses the needlessly wordy phrase "that have a comparable size", leading to awkwardness and redundancy.

Hence, A is the best answer choice.

To understand the concept of "Present Perfect Tense" on GMAT, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team
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The sentence tells us that Diesel engines burn less fuel than gasoline engines. They also emit less carbon dioxide and far fewer of the other dangerous gasses.

The first decision point is ‘as well as’ vs ‘and also.’ Usage of neither is incorrect.
‘and’ is a conjunction and will take a verb after it while ‘as well as’ is a preposition and will take a noun/gerund after it. Hence, both ‘as well as emitting’ and ‘and also emit’ make sense. Yes, ‘also’ is redundant here but sometimes we use it for emphasis so I cannot eliminate options based on that. I will prefer ‘as well as emitting’ but not rule out ‘and also emit’.
Option (B) uses ‘as well as emit’ which is incorrect. We need a noun/gerund after ‘as well as.’
Also, we do not need parallel structure with ‘as well as’ because it does not join equal elements. When ‘and’ joins elements, then they are parallel.

In options (C) and (D), ‘and also they emit…’ have multiple redundancies. Here ‘they’ is also redundant because the subject here is the same as the subject of the previous clause ‘diesel engines.’ So we do not need to repeat it.

Diesel engines burn less gasoline and emit far lesser carbon dioxide… (correct)

Also, it is better to use ‘that have been implicated’ and not ‘having been implicated.’
‘Having been implicated’ would normally require another action. It begs the question – then what?
Having been implicated in the case, he decided to meet a lawyer.
When we use only ‘having been implicated’ it seems to suggest that they were implicated but we know that they are presently implicated. Hence options (A) and (C) are better than (B), (D) and (E).

Option (C) commits the blunder of using far fewer (countable) with the quantity of carbon dioxide gas (uncountable).

Options (D) and (E) fail to mention carbon dioxide while mentioning ‘other gasses’ later on. When we say ‘other gasses,’ we need to have mentioned some gasses specifically before.
Hence, options (B), (C), (D) and (E) have multiple errors.

Option (A) is correct and preferable on all counts.

Answer (A)
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MISSION CRITICAL MODIFIER (As exception to touch rule of noun modifier)

A modifier need not necessarily modify the immediately preceding noun!!
“A heap of coins weighing more than one ton” - Now, is it the coins which are(each) weighing more than 1 ton or is it the heap which IS weighing more than 1 ton??

A “Mission-Critical” Modifier Falls Between (often an of-phrase that defines the noun). In these cases, the modifier modifies the entire noun phrase.

“He had a way OF DODGING OPPONENTS that impressed the scouts.”
• Without the modifier “of dodging Opponents” the noun “way” is meaningless. Next, The clause “that . . .” modifies the entire noun phrase “a way of dodging …” and not just the word “opponents”. . . Thus “of dodging opponents” is a Mission Critical Modifer

“Kelp is a natural fertilizer that has become popular among growers of heirloom tomatoes, who generally are willing to pay a premium for organic products”
• The clause “that . . .” correctly modifies ‘fertilizer’
• “who . . .” modifies the “growers”, despite the mission critical modifier in-between “of heirloom tomatoes”

Important Example (Mission Critical Modifier)
Q. Agricultural scientists have estimated that the annual loss by erosion of arable land caused by heavy rainfall and inadequate flood controls approaches two million acres per year.
A. the annual loss by erosion of arable land caused by heavy rainfall and inadequate flood controls approaches two million acres per year
B. the erosion of heavy rainfall and inadequate flood controls causes a loss of arable land approaching two million acres per year
C. erosion caused by heavy rainfall and inadequate flood controls results in a loss of arable land approaching two million acres per year (ignore "of arable land)(approaching modifies ‘Loss’)
D. an annual loss approaching two million acres of arable land per year results from erosion caused by heavy rainfall and inadequate flood controls
E. annually a loss of arable land approaching two million acres per year is caused by erosion due to heavy rainfall and inadequate flood controls

Important Examples (Mission Critical Modifier + parallelism with Past & present Participle)
Q. Industrialization and modern methods of insect control have improved the standard of living around the globe while at the same time they have introduced some 100,000 dangerous chemical pollutants, having gone virtually unregulated since they were developed more than 50 years ago.
A. while at the same time they have introduced some 100,000 dangerous chemical pollutants, having
B. while at the same time introducing some 100,000 dangerous chemical pollutants that have. (ignore the –of phrase, “of living . . . have)(improved parallel to introducing)
C. while they have introduced some 100,000 dangerous chemical pollutants at the same time, which have
D. but introducing some 100,000 dangerous chemical pollutants at the same time that have
E. but at the same time introducing some 100,000 dangerous chemical pollutant, having

Q. Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have been implicated in global warming.
A. of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have (ignore “of comparable . . . as)(burn parallel to emitting)
B. of comparable size, as well as emit far less carbon dioxide gas and far fewer of the other gasses having
C. of comparable size, and also they emit far fewer carbon dioxide and other gasses that have
D. that have a comparable size, and also they emit far fewer of the other gasses having
E. that have a comparable size, as well as emitting far fewer of the other gasses having

NOTE:
Improved = Past Participle and Introducing = Present Participle
Burn = Past Participle and Emitting = Present Participle


Took me a lot of effort to crack this!!

hope it helps all
Target760

Answer is A....wow good question. I found this on another website. I take no credit.

"as well as" is not a truly parallel construction; it creates a modifier that is not part of the skeleton of the original sentence. modifiers, as we know, don't have to be parallel to the main part of the sentence.

your best route here is just to memorize the fact that "...as well as VERBing" is an acceptable construction.

Step 1. Kick out C, D and E, because they are vastly distorting or deviating from the text’s intent. Original separates CO2 from the other gases and uses the uncountable comparative less because a gas is uncountable. By explicitly grouping other pollutants together and calling them gasses, the text permits the use of the countable comparative fewer to describe them. C bundles CO2 with other gases while D and E don’t even mention CO2. They can be dropped in one stroke.

Step 2. Between A and B, we have to grudgingly accept A, because of B’s indulgence in using 'having been’. However, it is no great solace that in GMAC quarters the expression ‘as well as’ plus participle is accepted as passable and parallel to a verb, despite its awkwardness.

Lesson: This is a GPREP question. Simply accept the official verdict, which is A
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The sentence is actually taken form NYT
http://www.nytimes.com/2001/05/27/busin ... iesel.html

I guess option B, D, and E are wrong because of "having been" which acts as a verb (with an incorrect tense)

I found A a little awkward because of the phrase/modifier ", as well as emitting" although it is a valid construction.

I'm not sure why C is wrong. Probably, because of the pronoun but even with that mistake, I would rather prefer C.
The subject of the sentence is "Diesel Engines" and when the sentence says " , and also they emit" it is quite biased to say "they" refers to the subject.

Can someone elaborate why A is preferred more than C? Are there any other mistakes? Is the pronoun usage absolutely invalid or is it okay?

Hi b2bt,

Let us take a look at the sentence structure for option C:

• Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size,
• and also they emit far fewer carbon dioxide and other gasses
o that have been implicated in global warming.

Now, there are two errors in this sentence:

Idiom Error: Using ‘fewer’ with the uncountable noun ‘carbon dioxide’ is incorrect. ‘Fewer’ is used to compare countable nouns. For uncountable nouns, ‘less’ is used.

• Joey took fewer steps than I did to reach to the sofa. (Steps- Countable Noun)
• Joey took less time than I did to reach to the sofa. (Time- Uncountable Noun)

Redundancy Error: Since the connector ‘and’ is already used in this sentence to represent the additional information, using ‘also’ is redundant.

Also, since the pronoun ‘they’ acts as the subject of the second clause, it refers to the noun that is the subject of the previous clause. (In this very point, the pronoun ‘it’ refers to ‘the pronoun they’.) So, there is no pronoun error in this option.

Hope this helps!
Deepak
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Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have been implicated in global warming.
A. of comparable size , as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have
B. of comparable size, as well as emit far less carbon dioxide gas and far fewer of the other gasses having

Hi,
Can someone please help me with below queries:
1.less carbon dioxide gas and far fewer of the other gases
I understand why to use "less" for CD [CD is un-countable] but what about "far fewer". Like CD, "the other gases" are also UC so why to use fewer,which is countable.
2. In the option B, is "having" modifying "the other gases" ?

I appreciate your inputs on the shared queries.


Just to add..
Another reason why B is wrong :
"emit" is a verb and hence a conjunction is req it to connect with burn.
Also, in option A emitting is the ing-modifier- modifying the preceding clause and makes sense with sub "Diesel engines ".
Regards.

Hi JarvisR,

Thanks for posting your doubt here.

1. The choice says that the car emits less carbon dioxide. This is correct because carbon dioxide as a gas cannot be counted. Hence, use of "less" is correct here. And you completely understand that point.

Now, the second part of the choice says that the car emits far fewer of the other gases. This means that the diesel run car does not emit as many toxic gases as gasoline run cars do. Say for example, if gasoline cars emit 5 toxic gases, the diesel run cars emit only 2 of these gasses. So here the sentence is talking about the number of toxic gases emitted by these two types of cars. Noe the types of gases are certainly countable. hence, use of "fewer" is correct here.

2. Yes, "having been..." modifies preceding noun entity "other gases". However, this expression is not as precise as "that have been implicated..."

Hope this helps.
Thanks.
SJ
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I found this explanation and thought I should share. Here it goes:

In C and E, fewer carbon dioxide is incorrect. Fewer is used to refer to something countable; carbon dioxide is not countable. (Please note that fewer other gases also is incorrect; the correct wording is fewer OF the other gases.) Eliminate C and E.

In D, less...other gases is incorrect. To discuss the NUMBER of the other gases, the correct wording is FEWER of the other gases. To discuss the AMOUNT of the other gases, the correct wording is LESS OF the other gases. Eliminate D.

In B, having been implicated is used -- incorrectly -- to modify gases. Having + past participle is used to indicate an action that:

-- is completed before the primary action attributed to the modified noun
-- provides context for the primary action attributed to the modified noun

For example:

Having enjoyed the book, John cannot wait to see the movie.

In the sentence above:
Having enjoyed refers to John.
Cannot wait is the primary action attributed to the modified noun John.
Having enjoyed was completed in the past; John cannot wait in the present.
Having enjoyed the book explains why John cannot wait.

In B, the other gases (the modified noun) are not performing a primary action. Hence the use of having + past participle is inappropriate. Eliminate B. [/color]

Hope this is helpful.
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mikemcgarry GMATNinja ...
please explain what the hell is going on in option A ... i have plucked almost a chunk of my hair. but still cannot understand what is actually going on in A. I mean do GMAT test makers live in US or Guatemala ?
please explain the structure of the sentence and please tell me what is role of each word and what is as well as doing there

I think there's move value in identifying the errors in the four incorrect answers than in diagramming the structure of the correct answer, but we do aim to please, so here goes:


In red we have an independent clause in which "diesel engines" serves as the subject. In blue we have a modifier providing additional information about the aforementioned diesel engines - they not only burn less fuel, but they emit less pollutants. And then in green we have a modifier describing "gasses." Most importantly: nothing egregiously wrong with the sentence.

The big takeaway: if you have one option that you struggle to make sense of, and four options in which you can identify a specific problem, you still know what the answer is.

I hope that helps!
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GMATNinja , daagh

Why is the use of "having been" in option B incorrect. Can somebody please elaborate?

"Having" is used to show that whatever action that follows "having" is done earlier.

For eg : Having finished his dinner, Shawn went to bed.

So "having" describes a past event before another event.

Now read ans choice B again
B. of comparable size, as well as emit far less carbon dioxide gas and far fewer of the other gasses having

- gasses were first implicated then there was emission?

The implication and emission are two independent events . That means they do not have to follow a verb sequence.

So using " having" after "gasses" means first there was implication then there is emission. We don't need a sequence here...

So it is wrong .. if you have any doubts lemme know.

Posted from my mobile device

Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have been implicated in global warming.


(A) of comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have-- This is the correct choice, emitting, far less Co2 and far fewer of the other gases.
(B) of comparable size, as well as emit far less carbon dioxide gas and far fewer of the other gasses having -- as well as 'emit' is wrong.

(C) of comparable size, and also they emit far fewer carbon dioxide and other gasses that have -- far fewer carbon-dioxide is wrong

(D) that have a comparable size, and also they emit far fewer of the other gasses having --- totally missing Co2 emission - wrong

(E) that have a comparable size, as well as emitting far fewer of the other gasses having--- totally missing Co2 emission. - wrong.
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