* leaching, the recovery of copper

[tim]

Glad you found what you were looking for!

[RonPurewal]

Thank you, Ron! Somehow, I didn't receive notification for your awesome replies!

i don't really know how those things work. (for someone who makes a large part of my living online, i am surprisingly inept at computer stuff)

[thanghnvn]

not easy

why d is wrong is the problem.

D is grammatical and logic but it is wrong because it present a distorted meaning. "as early as" should be an adverb modifying the preceding verb. in D, "as early as" is used as adjective. This meaning is not intended meaning.

[Aurion]

not easy

why d is wrong is the problem.

D is grammatical and logic but it is wrong because it present a distorted meaning. "as early as" should be an adverb modifying the preceding verb. in D, "as early as" is used as adjective. This meaning is not intended meaning.

"that" in choice D refers to "method", making the choice wrong when you fit with rest of the sentence.

[RonPurewal]

does anyone have a question? if so, please clarify. thanks.

[ruohongcao]

Hi Ron!

my question here is should there be a preposition before "as early as"?--Because without "as early as", this sentence would be reduced to " Leaching was a method___ the eighteenth century". Normally we would place "in" before "the eighteenth century", shouldn't there be one preposition?

Or "as early as" or any such phrase is used without a preposition in front of it?

Thank you!

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: http://www.manhattangmat.com/forums/pos ... tml#p45536
after you read that part, you should better understand why the nonessential modifier doesn't work here.

[SandeshM859]

Hi @Ron,

Great explanations! However, the amount of content has just confused me all over again. Could you please be kind enough to clarify my doubt, and it follows -
I had a make or break between C and E. In option C " ....was a
well established method of mineral extraction as early as....", well established is modifying method followed by Of preposition. Hence mineral extraction cannot be the subject. So my train of thoughts was how can method be as early as....I eliminated C.

In option E "had been a method of mineral extraction, well established...", I reasoned that had been a method [of mineral extraction], well established [the method was well established] is more logical because it suggests that method is well established.

Obviously I m wrong somewhere. Also I have been under impression that past perfect tense is used to indicate whenever there is a sequence of events that happened in past - one earlier past and the later past. And present perfect is used to indicate the ongoing effects of an action. In your earlier posts you have mentioned that past perfect is not right since Leeching is still a method.

Please clarify my doubts!
Many thanks

[Sage Pearce-Higgins]

Apologies for the delay in replying here. It looks like you're getting over-complicated with the modifier issue. Both 'well established as early as...' and 'that was well established as early as...' modify 'method of mineral extraction'. (Sure, 'of mineral extraction' is a modifier itself too, so technically 'method' is the thing being modified, but we don't need to go into that much detail.)

I'd encourage you to focus on the verb issue here. Check out the chapter in verbs in the SC Strategy Guide: the past perfect (the one with 'had been') is only used when we need to make clear that the action happened before some previous point. Here, 'was' is the correct tense to use.

[SandeshM859]

Apologies for the delay in replying here. It looks like you're getting over-complicated with the modifier issue. Both 'well established as early as...' and 'that was well established as early as...' modify 'method of mineral extraction'. (Sure, 'of mineral extraction' is a modifier itself too, so technically 'method' is the thing being modified, but we don't need to go into that much detail.)

I'd encourage you to focus on the verb issue here. Check out the chapter in verbs in the SC Strategy Guide: the past perfect (the one with 'had been') is only used when we need to make clear that the action happened before some previous point. Here, 'was' is the correct tense to use.

Glad you replied. So after reviewing the verb issue I learned that past perfect is used only to emphasize or clarify the sequence of events as in this happened first and that second (sorry for being vague but I hope you get my point), and since we are NOT clarifying a sequence of events here - saying leeching had been a method--------then some event happened later----- we are not using past perfect.

Please correct me if I am wrong here.

Thanks

[Sage Pearce-Higgins]

Yes, that's it.

[RAHULS852]

Hi RON/ Manhattan GMAT staff,

Sorry to open this thread.
I would like to ask one question regarding option A & B.
Does "Leaching,modifier,as a method" change the meaning from "Leaching,modifier,was a method" ?
Former means that there are many use of leaching & as a method of mineral extraction established in eighteenth century but later means that leaching is only a well established method & was established in eighteenth century.

Thanks

[Sage Pearce-Higgins]

It sounds like your asking what the difference is between these sentences:

1. Leaching, the recovery of copper from the drainage water of mines, as a method of extraction of minerals, was well-established as early as the eighteenth century...
2. Leaching, the recovery of copper from the drainage water of mines, was a well-established method of extraction of minerals as early as the eighteenth century...

To be clear, both 'the recovery of copper from the drainage water of mines' and 'as a method of the extraction of minerals' are modifiers here. These two sentences really just play around with the position of modifiers. Example 1 has 'as a method...' set of with commas, and example 2 has the same information places after the verb. You're right that example 1 suggests that there may be other uses of leaching, whereas example 2 defines leaching as a certain method. However, I think sentence 2 still leaves open the possibility that leaching has other uses. This is a nuance of meaning, or perhaps just a change in emphasis of the meaning.

However, notice that the problem doesn't test you directly on this nuance. There are much more significant problems with answers A and B in the problem. Although it's good that you considered this difference, it's more subtle than you need to see to solve SC problems.

[RAHULS852]

Thanks Sage for clarification.

[Sage Pearce-Higgins]

You're welcome. (And no need to repost my whole previous post in your reply!)