Air traffic routes over the North Pole are currently used by only two

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.

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that air traffic routes over the North Pole are currently used by only two or three planes a day, but a joint Canadian–Russian study has found that it is both feasible and desirable to open those routes to thousands more commercial planes a year.

Concepts tested here: Meaning + Modifiers + Verb Forms + Tenses + Idioms + Awkwardness/Redundancy

• The simple past tense is the correct tense for referring to hypothetical situations in the current time frame.
• 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.
• The simple past tense is used to refer to actions that concluded in the past
• In a “phrase + comma + noun” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.

A: This answer choice incorrectly uses the simple past tense verb "found" 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, and the simple past tense is used to refer to actions that concluded in the past. Moreover, Option A incorrectly uses the simple present tense verb "are" to refer to a hypothetical action in the current time frame; remember, the simple past tense is the correct tense for referring to hypothetical situations in the current time frame. Further, Option A incorrectly uses the unidiomatic construction "both A as well as B"; remember, “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable. Additionally, Option A uses the passive voice construction "it was found by a joint Canadian–Russian study to be", leading to awkwardness and redundancy.

B: This answer choice incorrectly uses "Currently used by only two or three planes a day" to modify "a joint Canadian–Russian study", incorrectly implying that a joint Canadian–Russian study is currently used by only two or three planes a day; the intended meaning is that air traffic routes over the North Pole are currently used by only two or three planes a day; remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Further, Option B incorrectly uses the simple present tense verb "are" to refer to a hypothetical action in the current time frame; remember, the simple past tense is the correct tense for referring to hypothetical situations in the current time frame.

C: This answer choice fails to form a complete sentence; as "finding" is a present participle ("verb+ing") acting as a modifier, there is no active verb to act upon the subject noun "A joint Canadian–Russian study".

D: Correct. This answer choice acts upon the independent subject noun "a joint Canadian–Russian study" with the active verb "has found" to form a complete thought, leading to a complete sentence. Further, Option D avoids the meaning errors seen in Options B and E, as it uses the phrase "Although air traffic routes over the North Pole are currently used by only two or three planes a day"; the construction of this phrase conveys the intended meaning - that air traffic routes over the North Pole are currently used by only two or three planes a day, but it is both feasible and desirable to open those routes to thousands more commercial planes a year, as a joint Canadian–Russian study has found. Additionally, Option D correctly uses the present perfect tense verb "has found" to refer to an action that concluded in the past but continues to affect the present. Moreover, Option D avoids the tense error related to the use of hypotheticals, seen in Options A and B, as it presents no hypothetical actions. Option D also correctly uses the idiomatic construction "both A and B". Besides, Option D is free of any awkwardness or redundancy.

E: This answer choice alters the meaning of the sentence through the phrase "With air traffic routes over the North Pole currently used by only two or three planes a day"; the construction of this phrase incorrectly implies that because air traffic routes over the North Pole are currently used by only two or three planes a day, it is both feasible and desirable to open those routes to thousands more commercial planes a year, as a joint Canadian–Russian study has found; the intended meaning is that air traffic routes over the North Pole are currently used by only two or three planes a day, but it is both feasible and desirable to open those routes to thousands more commercial planes a year, as a joint Canadian–Russian study has found. Further, Option E uses the passive voice construction "has been found", leading to awkwardness and redundancy.

Hence, D is the best answer choice.

To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~1 minute):



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



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

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/

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.

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.

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.

Someone please explain why it is "is both feasible and desirable" shouldn't that be "are both feasible and desirale instead?

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.

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.

GMATNinja Does the use of the pronoun "it" in A and B is an issue? Especially in A. Or is just a case of placeholder IT?

The "it" in choice (A) is certainly confusing.

Stripping out a prepositional phrase in (A), we have "... it was found to be both feasible as well as desirable." The "it" seems to be the thing that was found to be both feasible as well as desirable. And what was that thing? Air traffic routes over the North Pole? Well, in that case, we would need a plural pronoun ("they") and a plural verb ("WERE found to be...").

Maybe the "it" refers to "if those routes are opened to thousands more commercial planes a year"... but using "it" to refer to an "if" clause doesn't really make sense--is "if those routes are opened to thousands more commercial planes a year" the thing that's feasible and desirable??

Yes, there are times when the GMAT uses a "placeholder it" (also known as a "dummy pronoun" or a "non-referential pronoun" if you enjoy random terminology), but it's a rare thing, and you don't need to worry about it too much. For more on non-referential pronouns, check out this rant about licking frozen doorknobs.

For whatever it's worth: if we wanted to use "it" as a "placeholder", we would need something like, "... it was found THAT opening air traffic routes over the North Pole would be both feasible and desirable if..." Luckily, we don't have an option like that here, so it's definitely not a "placeholder".

I hope this helps!

How I solve GMAT S C question in around 1 minute
It is possible! In order to nail an S C question in around 1 minute, two things are essential. We must have an in-depth knowledge of all GMAT S C error types tested, and we must approach a question with right strategy – your thought process.
Read this 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

Some questions are partly underlined and others are fully underlined. Often fully underlined questions are more challenging because in a partly underlined question, we get some clues from non-underlined portion of the sentence which makes it easy to latch on to right answer.

First step is to read the entire sentence and try to get a sense of what the author is trying to tell us while simultaneously identifying errors if any. Remember, understanding overall meaning is critical. With practice, it is possible to understand meaning of a sentence even if there are multiple errors there. This is actually first thing that we have to master – understanding the meaning of a GMAT S C question with errors present.
Going back to the question, I have read the sentence and found two errors:
1.it was found by a joint Canadian-Russian study: GMAT prefers active voice, so this should be in active voice – Canadian -Russian study has found
2. both feasible as well as desirable: This is incorrect form. It should be – both feasible and desirable
Now, I have vertically scanned on the first error and eliminated C and E. Only B and D are using ‘Canadian – Russian study has found’. I have moved on and vertically scanned on the second error but couldn’t eliminate any because both are using -both feasible and desirable
So, I went back to the beginning of option B and found that it is illogically saying ‘Canadian – Russian study is being used by planes’
I won’t waste any time; I will immediately click option D and move on. Usually it is advisable to read our answer option back in to the sentence but here no back in to the sentence as the whole sentence is underlined. we can skip it.
Strategy slightly varies with question. Good luck!

Joseph Priestly
Sr. GMAT Instructor
Hyderabad
INDIA

Dear GmatNinja and Experts,

I am little confused over E to drop. Please help with the clarification.

----Quote------
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.

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
----Unquote------

My assumptions
Part-1 With air traffic routes over the North Pole currently used by only two or three planes a day--- Simple present
Part-2 Opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study as both feasible and desirable--- Present perfect

I think past event is missing here which is required to refer present perfect event.
Is this correct to drop E or please correct me.

Thank you!

I don't think we necessarily need a past event to refer to a present perfect event. The use of the present perfect here ("has been found") simply indicates that the action could have happened at any time in the past right up to the present moment -- and the action may have spanned any amount of time: days, weeks, months, years...

In this context, we know that it happened at SOME point in the past, but we have no idea when. The present perfect can work in situations like these (here's another example).

So I'm okay with using the present perfect in (E). But I'd prefer to see "... has been found TO BE both feasible and desirable" instead of "... has been found AS both feasible and desirable".

A bigger issue in (E) is the logic of the opening modifier, "With air traffic routes..."

Typically, when we open a sentence with a prepositional phrase, that phrase will modify the action performed in the following clause.

• "With $100 and case of beer, Tim headed to his daughter's dance recital." What did Tim head to his daughter's dance recital with? $100 and a case of beer.

But in choice (E), "With air traffic routes..." seems to modify how the "opening... has been found." The opening has been found alongside air traffic routes? The opening had been found by using air traffic routes? Neither interpretation makes sense. Because of the illogical modification, (E) is no good.

I hope that helps!

MyGuruStefan Thanks for that wonderful explanation.
The use of the pronoun "It" is an interesting one here. As per Magoosh - https://magoosh.com/gmat/verbal/sentenc ... orrection/

• The empty IT, does NOT need to have an antecedent, unlike the other pronouns.
• The “empty it” is an “it” that appears at the beginning of a sentence or clause: this pronoun has no simple noun antecedent. The “empty it” often serves to make sentences more indirect and wordy, so usually they are not correct on the GMAT. For example:

4a) It is more expensive to dine out every night than to prepare one's own meals at home.
4b)
Dining out every night is more expensive than preparing one's own meals at home.

The first sentence is 100% grammatically correct, but it is wordy and indirect; the second is much more concise and powerful. That’s an example of an “empty it” making a sentence wordier and rhetorically weaker. This is most often the case, but in rare cases, the “empty it” is perfectly acceptable.

This makes me wonder, if IT is wrong here, due to an antecedent error or simply because it makes the sentence wordy?

The "it" is incorrect, not merely wordy, because the antecedent should be the closest immediately preceding or following possible singular noun, which would be either "day" or "study" neither of which would logically make sense in context. Therefore, this would not qualify as the so-called "empty it". I hope this clarifies your issue. ~Stefan