Diesel engines burn as much as 30% less fuel than gasoline engines of

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

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.

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.

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.

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

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)

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.

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!

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

Burn and emitting are not parallel, nor do they have to be, because as well as is a preposition in that sentence, and it is followed by a gerund (the -ing form, though not all -ings are gerunds). You can take a look at some examples here and here.

Saying
Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, as well as emitting far less carbon dioxide gas...

is the same (structurally) as
Diesel engines burn as much as 30% less fuel than gasoline engines of comparable size, in addition to emitting far less carbon dioxide gas...

To sum up: putting the -ing form of a verb is perfectly acceptable after as well as. This is something that you'll have to commit to memory, as the GMAT has used it in a few questions.

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

Yes, if we were using "and", we would want a simple parallel list of verbs without a comma (i.e. "Diesel engines burn {...} and emit {...}").


Parallelism is not confined to verbs. You can have a parallel list of nouns, adjectives, clauses*, etc. For more on parallelism, check out this video.

*For example, "Neuroscientists are now drawing solid conclusions about (1) how the human brain grows and (2) how babies acquire language."

Again, this is just a weird idiomatic point, so I wouldn't worry too much about it. Perhaps an easier example is something like this:

"Artificial grass often looks just as good as natural grass, while costing significantly less to maintain."

Of course we need to use "costing", not "costs" after the "while" because "while" is not a simple parallelism trigger like "and".

It's a similar story with "as well as". But this point is not likely to help you on test day, so please please don't stress over it.

"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

You're not alone! Ajitesh has an excellent post explaining the grammatical difference between the terms: "as well as" functions as a prepositional phrase providing additional information, while "and" is a conjunction that must be used to connect like forms. If you're not sure whether "as well as" is correct, try substituting "in addition to" and see if the sentence still makes sense.

Consider another example to see how the two constructions differ:

"As well as inadvertently setting the house on fire, Tim forgot to pick up his toddler from day care."

Here, "as well as" is part of a modifier. Notice that a "verb-ing" construction is part of this modifier, but we don't have "verb-ing" elsewhere. That's fine. "As well as" doesn't require parallel forms.

However, if we wished to convey a similar idea using "and" we'd have to write something like:

"Tim set the house on fire and forgot to pick-up his toddler from day-care."

Now, because "and" is a conjunction that has to connect things that are in the same grammatical form, we use two verbs, "set" and "forgot."

The takeaway: "as well as" functions as a modifier, but "and" functions as a connector that links parallel items.

I hope that helps!

"Emitting" seems to be describing the "diesel engines."

And it's not parallel to anything. We often treat "as well as" the same way we'd treat "and," but grammatically speaking, they're not the same. "And" is a conjunction, so it has to connect like forms. "As well as" functions like adverb, so while it could connect two similar elements, it doesn't have to. If there's no parallel marker, there's no need to go looking for parallelism.

That said, the engine seems to do two things: 1) it burns less fuel than gas and 2) it emits less carbon dioxide. It just happens to be the case that #1 is communicated via a verb and #2 is communicated via a modifier. There's nothing inherently wrong with that, so at this point, you'd want to move on to other issues.

I hope that clears things up!

I wouldn't treat "and also" as a definitive error. The "also" could be used as a point of emphasis, for instance. More importantly, here's one official question where it shows up in the correct answer.

The takeaway: unless the redundancy in question is truly glaring, you probably don't want to use it as a decision point.

I hope that helps a bit!