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

I'm sorry, I am not sure about that. In my perception 'which' refers back to air traffic routes correctly. Whatever follows the preposition is part of the prepositional phrase, which modifies the previous noun. Now, 'which' refers back to the last noun, hence, the noun 'routes' ('air traffic' would be the compound adjective). Manhattan Prep has some good material on this.

Likewise in your example, 'of the park' is a prepositional phrase, as also is 'for development'. The reason your example is correct is that 'which' refers back to the noun 'funding' which could be 'open to the public early next year' as well.

At least this is how I see it.

This interpretation is not correct.

This sentence is from The Official Guide for GMAT Verbal Review 2016.

Official explanation (from GMAT official guide): In this sentence, which clearly modifies park.

Ok, you are probably right. I don't understand the logic though. In my perception the GMAC applies the same rules always on every topic, regardkless of the question. The rule I know is that comma+'which' always refers back to the last noun before the comma.
Why does the explanation say that this option is correct compared to other answer choices? I don't have the material of 2016.

Posted from my mobile device

I am not understanding your question. I thought that just a couple of post back, you mentioned that which will not refer to the last noun before the comma, if that noun is a part of prepositional phrase.

I would be careful using the presence of “it” as the sole basis for elimination of answer A and other such sentence versions that use an expletive “it” as the Subject.

This kind of “it” may be acceptable when it is “pushing back” an Infinitive Phrase or a Substantive Noun Clause to later in the sentence.

In this sentence, the expletive “it” is indeed problematic but it may not always be the case.

Awkward Ex: “To study hard for the exam is crucial.”

—-Awkward, but not necessarily grammatically incorrect)

Better ex: “It is crucial to study hard for the exam.”

Awkward ex: “That he will get a high score on the exam is certain.”

—— awkward but not necessarily grammatically incorrect

Better ex: “It is certain that he will get a high score on the exam.”






Posted from my mobile device

All good points, although in this sentence the "it" clearly isn't expletive as the word is used in the referential form. Hooray for the ambiguities of English, though. Keep up the good GMAT verbal practice! ~Stefan

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.
1-1
S find O to be OC
I find the book interesting.
*
S+find+O (to be)
Russian study has found opening those routes to thousands more commercial planes a year to be both feasible and desirable. (E)
Russian study has found if those routes are opened to thousands more commercial planes a year to be both feasible and desirable.。


1-2
O is found by S to be OC/O is found to be OC by S
the book is found by me to be interesting.
the book is found to be interesting by me .
*
Opening those routes to thousands more commercial planes a year is found by Russian study to be both feasible and desirable.
Opening those routes to thousands more commercial planes a year is found to be both feasible and desirable by Russian study.


1-3
S find it to be OC O
I find it to be interesting the book
*
S+find+it (to be) OC O
Russian study has found it to be both feasible and desirable to open those routes to thousands more commercial planes a year. (C)
Russian study has found it to be both feasible and desirable if those routes are opened to thousands more commercial planes a yearIf

1-4
it is found by S to be OC O/it is found to be OC O by S/
it is found by me to be interesting the book /it is found to be interesting the book by me/
*
It is found by Russian study to be both feasible and desirable if those routes are opened to thousands more commercial planes a year.(A)

1-5
S find that S+V+C
*
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.

2.
when/if/whether can both use as adj/noun clause


noun clause: used to introduce a clause, often in indirect speech, that shows two or more possibilities
adjective clause: used to say that a particular thing can or will happen only after something else happens or becomes true





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-1
we can not use it for the whole thing(Air traffic routes over the North Pole are currently used by only two or three planes a day)
a-2
and we can not use it for expletive because:
"if" in this sentence means adjective clause: used to say that a particular thing can or will happen only after something else happens or becomes true
it for expletive+ tov/noun clause.
a-3
both feasible as well as desirable


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.
if-adv clause.

b-1
if S are..., it would be...
it(wrong) can not mean the whole sentence: air traffic routes over the North Pole are opened to thousands more commercial planes a year
would be(wrong)
if air traffic routes over the North Pole are opened to thousands more commercial planes a year, it is/will both feasible and desirable.
b-2
Currently used by only two or three planes a day, a joint Canadian–Russian study



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-1
S+V+O
c-2
both feasible as well as desirable

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.(OA)

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
opening those routes to thousands more commercial planes a year has been found by a joint Canadian—Russian study TO BE both feasible and desirable

GMATNinja MartyTargetTestPrep KarishmaB AndrewN

"currently used by" - use of currently means that it should be present continuous tense as the action is continuing in present time - why used is correct here - this makes it present perfect

They have not switched the tense. It is a passive construction.

Only 2-3 planes use the routes over NP.
Routes over NP are used by only 2-3 planes.
Present tense is shown by the use of 'are.'

Active - A does B.
Passive - B is done by 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. 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-has no singular referent, both-as well as is 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.
The starting modifier is modifying the study, which is 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.
Both-as well as is incorrect, it-has no singular referent

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
opening has been found by a joint Canadian—Russian study - incorrect structure & meaning