SC: Geologists

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parachuter2b: Newbie | Next Rank: 10 Posts; Posts: 8; Joined: Wed Jun 30, 2010 10:51 pm

by parachuter2b » Tue Aug 14, 2012 12:51 pm

I understand Ron's and Stacey's explanations here..quite helpful as usual

In fact I'd seen similar posts by them before, so eliminating options with 'changing' in them was not an issue for me. but what I still don't understand is how come there is no 'and' before 'changes' in the OA.
I'm not questioning the OA. I have no doubt it's correct. However, I was under the impression that if we have a list of parallel items in a sentence, the first two should be delimited by comma and the last one should be followed by 'and'. Isn't that correct?

I thought this is how we're supposed dissect this sentence:

Geologists believe that.. the signs for .. may include
1. fluctuations in ...
2. , titling and other deformation of ..
3. , changes in ..

Hence I thought it should be written like:
Geologists believe that the signs for .. may include 1, 2 and 3.

Please advice!

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lunarpower: GMAT Instructor; Posts: 3380; Joined: Mon Mar 03, 2008 1:20 amFollowed by: 1535 members; Thanked: 2256 times; GMAT Score:800

by lunarpower » Tue Aug 14, 2012 4:36 pm

parachuter2b wrote:Hence I thought it should be written like:
Geologists believe that the signs for .. may include 1, 2 and 3.

Please advice!

that's exactly the way you would write the list ... if the list actually had three elements.

take a look at the problem again; you are forgetting the fourth and final element in the list ("variations...")

Ron has been teaching various standardized tests for 20 years.

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vikram4689: Legendary Member; Posts: 1325; Joined: Sun Nov 01, 2009 6:24 amFollowed by: 14 members; Thanked: 105 times

by vikram4689 » Tue Aug 14, 2012 7:56 pm

i tried to understand difference in "variations in" and "variations among" but it seems i am over-complicating the issue https://www.beatthegmat.com/sc-geologist ... tml#489432
please explain with the help of some examples

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by lunarpower » Tue Aug 14, 2012 8:41 pm

ok, for this whole "variations in"/"variations among" thing -- here is the simplest possible way in which to understand the difference.
the chance that you will ever see this distinction on the exam again is extremely remote, so anything beyond a basic understanding is pretty much frivolous here.

variations in X among Y
..."X" represents the things that actually vary.
..."Y" represents the people or things in which the variations are found.

e.g., variations in eye color among Indian men
the meaning of this phrase should be self-explanatory. examine how "among" and "in" are used in this phrase, and then generalize that idea.

also, each of these constructions can be used by itself. for instance, you can just have variations in eye color (among all people, and/or in the case of people who have already been specified). you can also just have variations among Indian men (in general, unless some specific context has already been articulated).

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vikram4689: Legendary Member; Posts: 1325; Joined: Sun Nov 01, 2009 6:24 amFollowed by: 14 members; Thanked: 105 times

by vikram4689 » Tue Aug 14, 2012 9:29 pm

thanks. on that basis, can i say that option e) is incorrect because it says "variations among electrical properties" but does not specify what is actual varying thing among these electrical properties.
in the same way, "variation among indian men" would not mean anything if something that is actually varying is not specified before. however, "eye color variation among indian men" would be fine as it specifies what property/thing is getting varied

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by lunarpower » Tue Sep 04, 2012 5:52 am

vikram4689 wrote:thanks. on that basis, can i say that option e) is incorrect because it says "variations among electrical properties" but does not specify what is actual varying thing among these electrical properties.
in the same way, "variation among indian men" would not mean anything if something that is actually varying is not specified before. however, "eye color variation among indian men" would be fine as it specifies what property/thing is getting varied

well, i think you have the basic idea here.
there are, actually, circumstances under which "variation among x" (in general) would actually make sense. for instance, the following sentence is logical:
in general, there is more variation among x than among y, because the original gene pool of the former had greater diversity.

but, you have the main idea, which is all that really matters.

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ankit0703: Senior | Next Rank: 100 Posts; Posts: 51; Joined: Mon Apr 09, 2012 12:20 am; Thanked: 7 times

by ankit0703 » Tue Oct 23, 2012 5:11 am

Stacey Koprince wrote:I received a PM asking me to comment. So, beater, you're right - that's part of why these are wrong! They're not parallel and they're not even used in the correct form anyway.

If I'm talking about "changing the strain" - that implies something IS changing the strain. Same with "varying the properties" - something IS varying the properties. Both structure the clause as an action being performed on some noun.

Note that this doesn't happen with "tilting and other deformations" - you can't say something IS tilting and other deformations. That's because "tilting" isn't functioning as a verb in the sentence.

If you find a correctly constructed "-ing as a straight verb" structure, it will be preceded by some form of the verb "to be." She was studying like crazy. I have been working really hard.

Stacey could you please let me know whether the underlying sentences are correct or not?

1. Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting of the Earth's crust, changes in the measured stain across a fault zone, and variations in electrical properties of underground rocks.

2. Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting the Earth's crust, changes in the measured stain across a fault zone, and variations in electrical properties of underground rocks.

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by lunarpower » Sat Nov 24, 2012 11:36 am

ankit0703 wrote:Stacey could you...

fyi, stacey hasn't been on this forum for a couple of years.

please let me know whether the underlying sentences are correct or not?

1. Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting of the Earth's crust, changes in the measured stain across a fault zone, and variations in electrical properties of underground rocks.

this is the officially correct answer to the original problem. (please check it in the og verbal supplement, if you haven't already!) so, you definitely know the answer to this one.

2. Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting the Earth's crust, changes in the measured stain across a fault zone, and variations in electrical properties of underground rocks.

not parallel.
remember that decisions about parallelism should be comparative, not absolute -- that is, you don't have to formulate an ideal answer; you just have to decide which of the choices is most properly parallel (without being wrong, of course).
if you look at the form of the other three choices, it should be clear that tilting of the earth's crust is more parallel to those choices than is this version.

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[email protected]: Junior | Next Rank: 30 Posts; Posts: 20; Joined: Sun Oct 14, 2012 1:34 pm

by [email protected] » Sun Dec 09, 2012 8:52 am

lunarpower wrote:
beater wrote:Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earthï¿½s crust, changing the measured stain across a fault zone, and varying the electrical properties of underground rocks.

(A) changing the measured strain across a fault zone, and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

As per OG, in the original sentence changing and varying are used as verbs rather than nouns. I dont understand how that is true because an ing form needs to be preceded by a 'to be' verb to qualify as a verb. Am I missing something? Could someone please correct me. Thanks!
yeah. if these things were used as nouns, they'd be preceded by articles: the changing of the strain, etc. the first article here ("the changing") is the most important.

Hi Ron,

I'm not a native speaker and I also thought that "changing" is a noun in this sentence. Is that what you explained a general rule for ing-Verbs, => article + ing-Verb = Noun ?

Thanks a lot!

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by lunarpower » Mon Dec 10, 2012 3:59 am

[email protected] wrote:
lunarpower wrote:
beater wrote:Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earthï¿½s crust, changing the measured stain across a fault zone, and varying the electrical properties of underground rocks.

(A) changing the measured strain across a fault zone, and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

As per OG, in the original sentence changing and varying are used as verbs rather than nouns. I dont understand how that is true because an ing form needs to be preceded by a 'to be' verb to qualify as a verb. Am I missing something? Could someone please correct me. Thanks!
yeah. if these things were used as nouns, they'd be preceded by articles: the changing of the strain, etc. the first article here ("the changing") is the most important.
Hi Ron,

I'm not a native speaker and I also thought that "changing" is a noun in this sentence. Is that what you explained a general rule for ing-Verbs, => article + ing-Verb = Noun ?

Thanks a lot!

any rule of that sort won't be without exceptions.

in problems like this one, it's much better to eschew such "rules" and, instead, to concentrate on the extremely prominent parallelism in the sentence elements.
the first two elements are both "noun + preposition + stuff", so you definitely want a similar structure in the choice that you ultimately pick.

this is just one specific illustration of the extremely important idea that relationships between/among sentence elements are a lot more important than one-off rules.

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[email protected]: Junior | Next Rank: 30 Posts; Posts: 20; Joined: Sun Oct 14, 2012 1:34 pm

by [email protected] » Tue Dec 11, 2012 4:30 pm

Thanks Ron, that helped a lot!

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