Last year, both groups of scientists found that the glaciers in wester

Question

Last year, both groups of scientists found that the glaciers in western Greenland  had retreated far enough to set off an inherent instability in the ice sheet, one that experts have feared for decades .

(A) had retreated far enough to set off an inherent instability in the ice sheet, one that experts have feared for decades

(B) had retreated so far that it set off an inherent instability in the ice sheet, and it is one that experts for decades have feared

(C) had retreated so far that they set off an inherent instability in the ice sheet, one that experts for decades has feared

(D) have retreated far enough to set off an inherent instability in the ice sheet, one that experts feared for decades

(E) have retreated so far that they set off an inherent instability in the ice sheet, one feared by experts for decades

https://www.nytimes.com/2014/05/13/science/earth/collapse-of-parts-of-west-antarctica-ice-sheet-has-begun-scientists-say.html

Two scientific papers released on Monday by the journals Science and Geophysical Research Letters came to similar conclusions by different means. Both groups of scientists found that West Antarctic glaciers  had retreated far enough to set off an inherent instability in the ice sheet, one that experts have feared for decades . NASA called a telephone news conference Monday to highlight the urgency of the findings.

daagh · Accepted Answer

ameyaprabhu wrote

Step 1. the phrase is starting with the word 'one', which is an indefinite and singular pronoun. Of course what follows one is a noun modifier and hence not critical 
2. A singular pronoun as such will stand for another singular noun in the part prior to it.

3. Instability, Greenland, and Ice-sheet are the three eligible singular contenders.

4. Now some logic: Do the scientists fear Greenland or the ice sheet? Nope, they are there for long. However, instability is a negative factor that these learned people do fear.

5. If you are interested in jargons, this is known as appositive modification wherein, a noun tries to describe yet another noun

aditya8062 · Answer

A it is :  had retreated far enough to set off an inherent instability in the ice sheet, one that experts have feared for decades

faults (in bold) with others:

B) had retreated so far that  it  set off an inherent instability in the ice sheet, and  it  is one that experts for decades have feared------------> "IT" does not go with "glaciers"

C) had retreated so far that they set off an inherent instability in the ice sheet, one that experts for decades  has feared ----------> "EXPERTS" DOES not go with "HAS FEARED"

D)  have retreated  far enough to set off an inherent instability in the ice sheet, one that experts feared for decades---->  wrong TENSE sequence "FOUND" does not go correctly with "HAVE RETREATED" here  
 
E)  have retreated  so far that they set off an inherent instability in the ice sheet, one feared by experts for decades------------ >same as D

jogeshanand · Answer

Though I reached answer option A by POE, I have a doubt. Can some one please clarify ?

Q1. In option A   ,one that experts  have feared  for decades.  is a noun + noun clause -> noun modifier. Now, if we have   ,one that experts  feared  for decades.  will it be a wrong answer choice ? If yes, how ? please explain with examples from OG (if possible). What affect    have feared / feared   has on this answer choice ?

aditya8062 · Answer

"FOR DECADES"  gives a notion of continuity just as  "SINCE"  does, So present perfect  "have feared"  is preferable.

thangvietname · Answer

hard one

sequence of tense rules that if the main clause in the past tense, the that clause/ object clause is normally in the past tense. but there is a case in which the that clause is in present or present perfect tense.

I knew that watter boil at 100 degree c.

why "have done" is incorrect in d and e. ?

rohitt911 · Answer

IMO A

The sentence takes us back to the "last year", and refers to something which already took place prior to the last year. We always use had for these conditions. This eliminates D and E. Now B has a dubious "it", so we eliminate B. Between A and C, the later uses "has" for experts.

ameyaprabhu · Answer

can someone please explain what is the "one that experts have feared for decades" referring back to? (and how to correctly identify what this phrase is modifying)

sananoor · Answer

GMATNinja   GMATNinja Two  daagh   mikemcgarry

Isnt the use of one+that wrong 
Can someone clarify more on this one s i have seen few official questions where the use of *one+that* is wrong

mikemcgarry · Answer

Dear sananoor , I'm happy to respond.

My friend, many students, especially non-native speakers, imagine that it's possible to arrive at GMAT SC mastery by memorizing some chimerical "complete" set of grammar rules. This approach is profoundly misconceived and doomed to failure. Yes, there are a few important rules and patterns to learn, but a much greater part of understanding grammar comes from understanding how grammar & context are interdependent. Language exists to communicate meaning, and grammar is a vehicle to convey this meaning, so some of the requirements of grammar can shift with different meanings and different context. The way a non-native speaker develops a deep understand of the many contexts of a living language is to develop a rigorous habit of reading. See: How to Improve Your GMAT Verbal Score Here are a few basic thoughts about this situation. The word " one " is an indefinite pronoun that can refer to either a person or a thing. For some background, see: GMAT Sentence Correction: Indefinite Pronouns and Agreement GMAT Sentence Correction: Indefinite Pronouns and Logic It's quite true that if " one " refers to a person, then the GMAT would consider it wrong to use " that ," because this is considered both illogical and impolite. Any human being is a " who ," not a " that ," and grammar always should reflect this basic courtesy and respect for the fundamental value of each human person. That is one clear rule. If " one " refers to a thing, as it does in this sentence, then there's no general problem with the construction " one that ." The following are 100% correct sentences. I want to buy a new car, one that has manual transmission. After the publication of Ulysses , Joyce wrote his final novel , one that abandoned all established narrative conventions. The Treaty of Versailles codified a period of peace, one that was so punitively unbalanced that the reignition of hostilities may well have been inevitable. My friend, you said, " i have seen few official questions where the use of *one+that* is wrong ." If the " one " was referring to a person, then this would be perfectly understandable. If the " one " was referring to an object, a thing, as it is in this question, then I would have to see the entire sentence in context to understand it. If you find such an official question already posted here in GMAT Club, feel free to tag me in that thread to ask for my input. Does all this make sense? Mike

Mo2men · Answer

Veritas Solution

The most obvious decision point in this question is the tense choice between “had retreated” and “have retreated.” Since the scientists made this discovery in the past (past tense “found” is used and it was last year) you need to use the past perfect when describing actions before that. The present perfect “have retreated” cannot be used here as the action occurred before the scientists found it. Also, when paired with the simple past tense at the end in (D) and (E), the present perfect is particularly problematic. From this you can eliminate (D) and (E). In (B), the pronoun “it” is incorrect as it refers back to the plural noun “glaciers”. In (C) the “has feared” at the end is incorrect as it needs to be “that experts HAVE feared.” Correct answer is (A).

AkashM · Answer

Hi GMATNinja, GMATNinjaTwo, generis, hazelnut,

Can any one of you please tell me whether the usage of 'have feared' is correct in the OA.

If I am not wrong the scientists feared inherent instability or the occurrence of it for decades, but now that it has happened shouldn't they be worried about the consequences of it rather the thing itself. To me 'feared' makes a lot more sense.

Your help is very much appreciated.

lakshya14 · Answer

AndrewN  In (A) and (D), the decision point is tenses "had" and "have". In (A) with "had" the act of experts was before the act of glacier which happened last year.

Whereas in (D), "have" makes a problem by using for event which ended in the past.
Both looks problematic to me but (A) a bit less.

AndrewN · Answer

Hello,  lakshya14 . The decision between  had  or  have  retreated comes down to the answer to the question,  What was found  last year  ? We cannot reasonably argue that a finding from a year prior need be expressed in a present perfect tense, even if it could very well be true that glaciers would be continuing to retreat into the present time. As for the later split between  experts feared  or  experts have feared , I would call that one a push. I cannot lean on the context of the sentence to tell me whether scientists no longer fear such an occurrence, as option (D) conveys, or whether that fear extends into the present (option (A)). When in doubt, choose the answer that is harder to argue against, and that answer here is (A). (I originally liked  so far  more than  far enough , but I had to abandon my preference when I sought to make sense of the second half of the sentence, particularly in (C).)

I hope that helps. Thank you for thinking to ask me.

- Andrew

41396302717 · Answer

Hello  generis ,  mikemcgarry ,  GMATNinja ,  VeritasKarishma ,
 AndrewN

I have a doubt regarding the OA.
The OA uses the present perfect verb had and hence gives us the reason to believe that the retreating of the glacier has come to a halt, that too before the scientists found out, but the stem nowhere gives us the indication that the retreating has stopped.
Therefore, I think that in this situation "have" will be a better usage than "had" and also had there been an option with "have" for the first verb and "have" for the second verb too, that option would have been the correct answer.

Please clarify the doubt.
Thank you guys in advance.

vinay19294 · Answer

To set off inherent instability. Won???t it indicate glaciers retreated intentionally to set off inherent instability.

ExpertsGlobal5 · Answer

Hello  vinay19294 ,

We hope this finds you well.

To answer your query, this sentence uses the construction "enough + to", which is used to convey adequacy rather than purpose or intent of the action.

We hope this helps.
All the best!
Experts' Global Team

Last year, both groups of scientists found that the glaciers in wester

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Last year, both groups of scientists found that the glaciers in wester

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