When dealing with fully underlined sentences such as this, try to identify a single error first to streamline the elimination process for maximum efficiency. In the sentence as written, the pronoun "it" is ambiguous because it lacks a clear antecedent. Eliminate A and look for any choices that also include ambiguous pronouns. Choices B and C also include the ambiguous or otherwise erroneous pronouns "it" and "which" that do not correctly and clearly refer to a prior subject. Eliminate B and C as well for their pronoun errors.

Choice D properly orders the information in the sentence and eliminates the ambiguous pronouns. Choice E eliminates the main predicate phrasing of the sentence by omitting "are" and leaves it without a clear subject-verb pairing. It also includes the incorrect idiom "found... as", which should be "found... to be". Eliminate choice E. The correct answer is D.
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Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
Correct parallel market is BOTH X AND Y. BUT is used to show contradiction, but in this option such contradiction is not present. Hence Incorrect.

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.
What is "Currently used by only two or three planes"....? I guess answer has to be AIR TRAFFIC ROUTES. But in this option answer is "Canadian - Russian Study". Moreover, Antecedent of IT is not present. Hence Incorrect.

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.
This sentence is a FRAGMENT. Correct parallel market is BOTH X AND Y. WHICH is modifying NORTH POLE, an incorrect use. Hence Incorrect.

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.
CORRECT

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable
Study found that opening those routes is feasible....- Correct since conveying original intent.
Study found opening is feasible....- Incorrect since it distorts original intent.
Hence INCORRECT

question: is both A as well as B correct?
I eliminated A because of this.

Hi,
Correct Idiom is both A and B . You can eliminate option A for this error.

look at choice e
with+noun+doing/do-ed/adjective can work as adverbial , showing an attendent circumstance, but this phrase can not show a contrast as "although-clause" dose.

so, the meaning relation between "with-phrase' and the main clause is not logical. gmat test the split between with-phrase and although-clause many times on gmatprep

be ready to differentiate between the two on the test.

Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
"IT" cannot refer to plural "ROUTES"

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.
After the modifier "Currently used by ...", the subject which the modifier is modifying shall follow.

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.
The Subject "A joint Canadian Russian Study" has NO verb at all ...Run on sentence.

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.
Perfect ..All subject verb pairs and the modifiers are highlighted in different colors.

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable.
A separate Character (Subject) with its separate story (verb) is required...the "with air traffic..." clause is in no justifies attaching of such additional information to the main clause.
Refer this for more clarification :
https://magoosh.com/gmat/2015/with-noun-participle-on-gmat-sentence-correction/
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Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year. --- 1. Both as well as is a serious error; 2. If the conditional clause is in present tense, the main clause cannot be in past tense.

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable. --- Modification problem

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year. - A fragment
D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable. ---- Error free

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable-- The 'with' modifier clause, should be followed by the doer of the action, namely the Canadian- Russian study after the comma. As such, the modification is faulty.
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Hi Experts GMATNinja GMATNinjaTwo

I had slightly different approach to get to OA, and want to validate if its correct:
(A) study to be both feasible as well as desirable seems incorrect when compared with :study is both feasible and desirable. the verb to + something denotes purpose and study in not performing a specific function here. I do not see issue with IT since it can be used as demonstrative pronoun for eg It is raining. Here there is no logical antecedent for IT
(B) later part of sentence: it would be .. is not connected using FANBOYS connector
(C) the phrase which are had SV no agreement since study (singular) requires singular verb : is currently used
(D)correctly brings out contrast and opening those routes is subject for is both feasible and desirable, makes more sense than (A)
(E) contrast is lost here.
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Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
A is out because the phrase "desirable if those routes are opened" should read "desirable that those routes are opened. The former suggests that something is desirable only if the routes are opened.

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.
B is wrong because it suggests the study is used by only two or three planes a day.

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.
C contains a dangling modifier, "which are currently used by only two or three planes a day." It is dangling because it is separated from the study that it modifies.

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.
D is the best only because the rest are not. The opening word "although" has nothing to do with the fact that a joint study reached a finding. Instead, there should be and "and" after "a day...."

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable
E is a sentence expressed in the passive voice, always to be avoided, and in this case, awkwardly so.

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though the sentence is underlined, the same method is applied. first, try to realize grammatical roles of each phrase when you read. immediately, when you see any grammatical role not logic, you find an error. good knowledge of grammar patterns and a sense of logic is required.

apply above rule

read choice a. at first , we see "it" is not clear. "it is found to be" is good pattern if "it" is real subject, not fake subject. for example,
the cup is good. it is found useful.
if "it" is fake subject. we have only following pattern " it is found that".
for example,
it is found that he get very good score on gmat.

so, when we see "it" in choice a, we have to know two patterns with "it" (very good grammar is required). then , we see "it" has some problem.

above process is basic to read a choice.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.
The correct idiom is BOTH X AND Y
ELIMINATE

B. Currently used by only two or three planes a day (hmmm, WHAT is used by only two or three planes a day?), a joint Canadian–Russian study (a joint study was used by two or three planes a day?? THIS MAKES NO SENSE) has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.
ELIMINATE

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.
The correct idiom is BOTH X AND Y
ELIMINATE

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable
. . . has been found AS is unidiomatic (should be FOUND TO BE)
ELIMINATE

Answer: D

ASIDE: In many cases, an incorrect answer choice has several issues. I have just pointed out one issue.
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A. Use of "as well as" is incorrect with "both". Both should be followed by "and"; both x and y

B. "A joint Canadian–Russian study" is not being used by two or three planes. Comma should be followed by "air traffic routes".

C. Same as A.

D. Correct

E. We don't need a present perfect tense.
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You are correct; I eliminated A for that very reason. The correct idiom should be "both A and B"

In my opinion, COMMA + WHICH is correctly placed here and refers back to "air traffic routes" AND NOT "the North Pole" because "the North Pole" is the object of preposition "over the North Pole" and therefore, is not the closest preceding main noun.

Please tell me whether I am right or wrong.

Hi parthjain68, which can refer to object of preposition. There are numerous such official questions. For example:

The commission proposed that funding for development of the park, which could be open to the public early next year, be obtained through a local bond issue.

Here, which refers to park (park is the object of preposition of in this example).

However, in the sentence under consideration, which cannot modify North Pole because the sentence says which are. So, which can only modify a plural Noun in this sentence.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses modifier concepts of which, their application and examples in significant detail. If someone is interested, PM me your email-id; I can mail the corresponding section.
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Someone please explain why it is "is both feasible and desirable" shouldn't that be "are both feasible and desirale instead?

mokshaykumar400@gmail.com

My two cents: Here is how I would break the sentence in to its clauses:

Although air traffic routes over the North Pole are currently used by only two or three planes a day,

a joint Canadian–Russian study has found that

opening those routes to thousands more commercial planes a year is both feasible and desirable.

You may refer to this article to know why
verb-ing behaves as a noun.

Hope this helps.
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Hi mokshay, what you ask, is a subject-verb agreement issue.

The question you should be asking is: What is/are both feasible and desirable?

From the context, it should be clear that opening (those routes to thousands more commercial planes a year) is both feasible and desirable.

Since opening is the subject, the correct verb is is.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses Subject-Verb agreement, its application and examples in significant detail. If someone is interested, PM me your email-id; I can mail the corresponding section.
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Hello Everyone!

Let's take a closer look at this question, and figure out the best way to tackle it to find the right answer! Here is the original question:

Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable.

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year.

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable.


Whenever we see the entire sentence underlined, we know right away that we can start by looking at large grammatical issues first. Here are two main problems that you can look for when tackling whole-sentence GMAT questions:

1. Modifiers
2. Conciseness / Wordiness

Let's start by looking for any problems we can find with modifiers. Make sure to look carefully for dangling modifiers, misplaced modifiers, modifier-antecedent disagreement, or modifiers with no clear antecedent. Here is how each answer stacks up:

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year. --> OK (no modifiers to deal with)

B. Currently used by only two or three planes a day, a joint Canadian–Russian study has found that if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it would be both feasible and desirable. --> MISPLACED MODIFIER / CHANGED INTENDED MEANING (The phrase "Currently used by only two or three planes a day" is a modifier that SHOULD come before "air traffic routes." Instead, this sentence suggests that the Canadian-Russian study is only used by only two or three planes a day, which doesn't make logical sense.)

C. A joint Canadian–Russian study, finding it to be both feasible as well as desirable to open air traffic routes over the North Pole, which are currently used by only two or three planes a day, to thousands more commercial planes a year. --> SENTENCE FRAGMENT / MODIFIERS WITH NO CLEAR ANTECEDENT (The subject "A joint Canadian-Russian study" has no verb to go with it - it's just a subject with 3 modifier phrases stacked up after it. Since this lacks a clear verb, it is a sentence fragment and cannot be the right option.)

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable. --> OK (No modifiers to deal with)

E. With air traffic routes over the North Pole currently used by only two or three planes a day, opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable --> PASSIVE VOICE (Okay, so this isn't a modifier problem, but after reading this over quickly, it's clear that this sentence is using passive voice, which is a major no-no on the GMAT Sentence Correction section!)

We can eliminate options B, C, and E because they have issues with modifiers or passive voice.Now that we have our options narrowed down to A & D, let's look at what's different about each option so we can find the best answer. For this part, let's focus on #2 on our list: conciseness.

A. Air traffic routes over the North Pole are currently used by only two or three planes a day, but it was found by a joint Canadian–Russian study to be both feasible as well as desirable if those routes are opened to thousands more commercial planes a year.

Option A is INCORRECT because it's overly wordy! There is no need to use the passive voice to say "it was found by X," when you could just say, "X found it." The GMAT also prefers that students use "is" instead of "to be," and they also prefer to use "and" instead of "as well as."

D. Although air traffic routes over the North Pole are currently used by only two or three planes a day, a joint Canadian–Russian study has found that opening those routes to thousands more commercial planes a year is both feasible and desirable.

Option D is CORRECT because it is concise, conveys the correct meaning, and doesn't have any problems with unclear or misplaced modifiers!

There you have it - option D is the best answer!


Don't study for the GMAT. Train for it.
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