* leaching, the recovery of copper

[rx_11]

leaching, the recovery of copper from the drainage water of mines, as a method of the extraction of minerals, it was well established as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process.

(A) as a method of the extraction of minerals, it was well established
(B) as a method of the extraction of minerals well established
(C) was a well-established method of mineral extraction
(D) was a well-established method of extracting mineral that was
(E) had been a method of mineral extraction, well established


Source: GMAT prep.

(I have searched the forum and this question has already been posted in MGMAT forum. But it was posted in the General Verbal Question, and no experts answered. so I create a new post here. )



Dear instructors,

The OA of this question is C. But I don't quite understand which two parts are being compared in this sentense. Could u explain what is used to compare with "the eighteenth century" in C?

Moreover, could u explain what's wrong with E?

Thanks very much!

[RonPurewal]

Source: GMAT prep.

did you see this problem in the gmat prep software with your own eyes?

it's not badly written -- i.e., if it's a third-party question, then its author did a nice job -- but i can't find it cited elsewhere as a gmat prep problem.
i do know that it's in "1000sc", but please understand that the majority of 1000sc problems are NOT official. (in fact, it's quite likely that the entire corpus of official GMAT SC problems consists of fewer than 1000 problems.)

The OA of this question is C. But I don't quite understand which two parts are being compared in this sentense. Could u explain what is used to compare with "the eighteenth century" in C?

"as early as" and "as late as" are not comparisons; they are ways of placing boundaries on the date of some event. for another use of this same construction, check out the non-underlined part of problem #25 in og12 (which i'm not allowed to reproduce here).

Moreover, could u explain what's wrong with E?

inappropriate tense.
if the past perfect is used to describe a state or description of something (as opposed to an action verb), it should generally be used to describe a state/description that is no longer the case. since leaching is presumably still an extraction method (this is not the sort of thing that is subject to change), the past perfect is inappropriate.

also, the modifier (starting with "well established") shouldn't be a nonessential modifier, i.e., it shouldn't be set off by commas.
this isn't generally a difference that's tested, so i'll defer the explanation to the following thread, on which i wrote about it: post45536.html#p45536
after you read that part, you should better understand why the nonessential modifier doesn't work here.

[rx_11]

Hi, Ron,

This is a problem from GMAT prep test 2, I promise. I've met this question many times in GMAT prep. Feel sorry that I don't know how to add a screenshot. Hope somebody in the future can help me prove that.. :)

BTW, thanks very much for the explanation. Fully understand it now. :)

[RonPurewal]

Hi, Ron,

This is a problem from GMAT prep test 2, I promise. I've met this question many times in GMAT prep. Feel sorry that I don't know how to add a screenshot. Hope somebody in the future can help me prove that.. :)

BTW, thanks very much for the explanation. Fully understand it now. :)

ok.
this problem is definitely written in the style of the official problems, so, sure.
glad to help

[manassingh]

i narrowed down the answer to C vs D.

Here is why i think D is wrong.

Ron, Can you please validate my theory -

leaching, the recovery of copper from the drainage water of mines, as a method of the extraction of minerals, it was well established as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process.

D - was a well-established method of extracting mineral that was

lets put D in the sentence -


leaching, the recovery of copper from the drainage water of mines, was a well-established method of extracting mineral that[method] was
as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process

Since that is referring to method, the sentence does not make sense. Hence D is wrong.

[RonPurewal]

leaching, the recovery of copper from the drainage water of mines, was a well-established method of extracting mineral that[method] was
as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process

Since that is referring to method, the sentence does not make sense. Hence D is wrong.

you got it.

--

importantly, in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2.
for instance:
the library has a new method of sorting cd's that makes certain genres of music easier to find. --> here, "that makes..." refers to the method of sorting.
the library has a new method of sorting cd's that don't fit into any of the traditional musical genres. --> here, "that don't fit..." refers to the cd's, not the method.
both sentences are correct.

however, in the example above, either of these two interpretations leads to an absurd sentence -- neither the method (= NOUN1) nor the mineral (= NOUN2) "was as early as the 18th century" -- so this option is flat-out incorrect.

[manassingh]

Many thanks Ron.

[jnelson0612]

Good, thanks everyone.

[kvitkod]

Hi Ron

however, in the example above, either of these two interpretations leads to an absurd sentence -- neither the method (= NOUN1) nor the mineral (= NOUN2) "was as early as the 18th century" -- so this option is flat-out incorrect.

I think that "method" can be modified by "was as early as the 18th century". We need another reason for elimination (d). For me "of extracting mineral" looks worse than "of mineral extraction" since the latter uses noun rather than gerund. Please correct me.

[ranjeet1975]

leaching, the recovery of copper from the drainage water of mines, was a well-established method of extracting mineral that[method] was
as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process

Since that is referring to method, the sentence does not make sense. Hence D is wrong.

you got it.

--

importantly, in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2.
for instance:
the library has a new method of sorting cd's that makes certain genres of music easier to find. --> here, "that makes..." refers to the method of sorting.
the library has a new method of sorting cd's that don't fit into any of the traditional musical genres. --> here, "that don't fit..." refers to the cd's, not the method.
both sentences are correct.

however, in the example above, either of these two interpretations leads to an absurd sentence -- neither the method (= NOUN1) nor the mineral (= NOUN2) "was as early as the 18th century" -- so this option is flat-out incorrect.

Please read the following question:

Coronary angiography, a sophisticated method for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses x-rays to observe cardiac function.
(A) for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(B) for diagnosing coronary disease involving the introduction of a dye into the arteries of heart, is now administered selectively, because of using
(C) for diagnosing coronary disease, involves the introduction of dye into the arteries of the heart and is now administered selectively, because it uses
(D) to diagnose coronary disease that involves the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(E) to diagnose coronary disease involving the introduction of a dye into the arteries of the heart, which is now administered selectively, uses

C is the official answer and it is right.

But if we go by the rule:

in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2

Why then D is not right.

[messi10]

Hi Ranjeet,

One of the reasons why I wouldn't choose D is the amount of information that is set as a non-essential modifier.

Choosing choice D, the sentence reads:

Coronary angiography, a sophisticated method to diagnose coronary disease that involves the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses x-rays to observe cardiac function.

Note that all of the underlined part is describing the Coronary angiography as a non-essential modifier when some of it is actually essential to make a sensible sentence.

Choice C correctly uses only "a sophisticated method for diagnosing coronary disease" as the non-essential modifier

Hope this helps

Regards

Sunil

[RonPurewal]

Please read the following question:

Coronary angiography, a sophisticated method for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses x-rays to observe cardiac function.
(A) for diagnosing coronary disease involving the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(B) for diagnosing coronary disease involving the introduction of a dye into the arteries of heart, is now administered selectively, because of using
(C) for diagnosing coronary disease, involves the introduction of dye into the arteries of the heart and is now administered selectively, because it uses
(D) to diagnose coronary disease that involves the introduction of a dye into the arteries of the heart, is now administered selectively, because it uses
(E) to diagnose coronary disease involving the introduction of a dye into the arteries of the heart, which is now administered selectively, uses

C is the official answer and it is right.

But if we go by the rule:

in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2

Why then D is not right.

please read the forum rules -- if you want to post a new problem, you must post that problem in a separate thread.
also, you must give the SOURCE of the problem (the original source -- not another forum) when you re-post it.

if this problem is not from the GMAT PREP SOFTWARE, then it does not belong in this folder; it belongs in the general verbal folder -- unless it is from one of our banned sources, in which case you can't post it here.

we will delete the posts containing this question in the next 3-5 days; please re-post a new thread, per the forum rules. thank you in advance.

[saintjingjing]

leaching, the recovery of copper from the drainage water of mines, was a well-established method of extracting mineral that[method] was
as early as the eighteenth century, but until about 25 years ago miners did not realize that bacteria taken an active part in the process

Since that is referring to method, the sentence does not make sense. Hence D is wrong.

you got it.

--

importantly, in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2.
for instance:
the library has a new method of sorting cd's that makes certain genres of music easier to find. --> here, "that makes..." refers to the method of sorting.
the library has a new method of sorting cd's that don't fit into any of the traditional musical genres. --> here, "that don't fit..." refers to the cd's, not the method.
both sentences are correct.

however, in the example above, either of these two interpretations leads to an absurd sentence -- neither the method (= NOUN1) nor the mineral (= NOUN2) "was as early as the 18th century" -- so this option is flat-out incorrect.

en, ron, I still do not sure it
I see what you say in a post about difference about non-essential and essential clause.
but, why in D, as early as the 18 centuary should not modify method?
I guess, only guess, may be compared with C ,correct one, D method that was as early as... is not more logic than B as early as 18 C (--> modify the clause before but)
need your help. thanks

[RonPurewal]

en, ron,

what does "en" mean?

but, why in D, as early as the 18 centuary should not modify method?

you can't say that a NOUN was "as early as the 18th century", unless that noun is literally a time period. (e.g., the end of Era X may have been as early as the 18th century.)

I guess, only guess, may be compared with C ,correct one, D method that was as early as... is not more logic than B as early as 18 C (--> modify the clause before but)
need your help. thanks

i'm sorry, but i don't understand what you've written here.

[zhongshanlh]

hi,Ron,having read all the posts in this thread,i still have 2 questions.

1.in option D--->was a well-established method of extracting mineral that was
i know that in this option the word "that" refers to the phrase "method of extracting mineral" as a whole, but i still do not know why it is wrong??

2.i have read the link given to us about the essential and nonessential modifiers, but i am still not clear why the phrase"well established" is wrong in option E.

please clarify and thank you so much.