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 take an active part in the process.
Meaning Analysis: Leaching is a process used to extract copper from the drainage water of mines. This method was established in the eighteenth century. 25 years ago miners realized that bacteria play an active role in this method. Prior, they had no clue!
Sentence Structure:Leaching
(subject), the recovery of copper from the drainage water of mines,
(noun + noun modifier modifying the subject "leaching") (notice the modifier is in a comma pair this clearly means that it is just acting as some additional information) as a method
("as" is used as a comparison marker ; "as + noun" is used to state the function of the entity. Here "leaching" is a "method"), it
(subject) (it refers to leaching) (element 1 of comparison)was well established
(verb)as early as
(comparison marker)the eighteenth century
(element 2 of comparison), but until about 25 years ago
(contextual word "but" indicates a change of tone/idea/direction)miners
(subject)did not realize
(verb)that
(connector)bacteria
(plural subject)take
(plural verb)an active part in the process.
(object of the sentence)Quote:
A. as a method of the extraction of minerals, it was well established
We have the subject "leaching" without a verb and thus there is a SV error. Also notice "method of the extraction", this structure just makes the sentence inferior.
Quote:
B. as a method of the extraction of minerals well established
Same errors of choice (A) are repeated. Note that "established" is the adjective modifying "leaching" and is not acting as a verb. "well" on the other hand is the adverb modifying the adjective "established"
Quote:
C. was a well-established method of mineral extraction
Correct. The subject "leaching" is given a simple past tense verb "was established". Notice, by removing article "the" we have "a method of mineral extraction" this is much better compared to "a method of
the mineral extraction"
Takeaway:
When "the" is used we are trying to go specific. This means that if we say "the leaching" we aren't talking about "leaching" in general rather, we are talking about one specific
type of "leaching and that is certainly illogical.
(1) Buy me a book --> buy me any book.
(2) Buy me the book --> we are talking about a specific book out here.
Quote:
D. was a well-established method of extracting mineral that was
"That" refers to "mineral" and thus the sentence "was as early as the eighteenth century" refers to "mineral". This is clearly illogical. We want to say that "leaching method" was established in the eighteenth century and not that "the minerals extracted from this method" was established in the eighteenth century.
Quote:
E. had been a method of mineral extraction, well established
If one focuses on the meaning of the sentence he/she will be able to eliminate this option. By using past perfect tense "had been" we are now saying that the "leaching" at one time was a method of extracting minerals and now it no longer is. This is certainly not what the author is trying to convey.
Correct choice:
(C)Learning:-
a noun + noun modifier is essentially a noun modifier that modifies a noun. "
Ron, the smart guy with brown hair, is studying for the test." The smart guy is a noun and "with brown hair" is a prepositional phrase modifying the noun "the smart guy". And combined this entire modifier "
the smart guy with brown hair" is modifying our main subject "Ron"
Well explained by egmat in the following links:-1. What is a noun + noun modifier https://e-gmat.com/blogs/noun-noun-modi ... ny-entity/2. Noun + noun modifier Vs an action modifier https://gmatclub.com/forum/noun-noun-mo ... 37569.html