To map Earth's interior, geologists use a network of seismometers to

Hi Brego7, this is the position I would go with, though the nearest clause would be a preference.

In light of this, option C in the sentence under consideration is absolutely fine, since the nearest clause is:

that (seismic waves) originate in the earth's crust and ricochet around its interior

So, the participial phrase (traveling most rapidly through...) is correctly modifying the subject (seismic waves) of the nearest preceding clause.

so from this question can I infer that ambiguity in verb-ing's reference is allowed,

also verb-ed and which function same when used after the clause.

Hi Anand, such participial phrases (that are used towards the end of a sentence/clause and are preceded by a comma) modify the subject of the preceding clause.

In option C, participial phrase traveling most rapidly.. correctly modifies seismic waves, the subject of the preceding clause.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses participial phrases, their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

GMATNinja
Hi, Mr Ninja
I am not a native speaker so my writing can be confusing. I've been a big fan of you and Ron since I started preparing for GMAT.
Choice B：interior, which travel most rapidly through cold, dense regions, and more slowly

QUESTION 1: When we look at option B in this problem, should I think of "which travel most...." is trying to modify the noun "waves" and say "this construction is terrible because it puts two modifiers(modifying the same noun) together" or should I think of the rule that "which" modifies the preceded noun and say "the verb (travel) should be singular?


MY OPINION： I prefer the first thought process because "which" doesn't alway modify the preceding noun, it could sometimes jump around.

QUESTION 2
I also have another question, since "choose the answer that is most effective.... in conveying message" is mentioned in the OG,(OG instruction to SC I believe) should I consider construction when I eliminate 3 choices and end up with 2 choices(when I really have to pick one out of the two)?

Regarding your first question, I think you should consider BOTH of the points you mentioned when eliminating choice (B)!

You are right that "which" doesn't always modify the preceding noun, but in this case we have an entire clause in between the "which" and the thing it should modify. That alone is a pretty strong vote against (B). And, as you said, the "which" can't possibly modify the closest noun ("interior"), since that would require using a singular verb ("travels").

But let's say we're okay with that and assume that "which" correctly modifies "waves". In that case we'd want to use a parallel structure, i.e.: "... seismic waves (1) that originate and ricochet AND (2) that travel...". Instead, choice (B) essentially gives us, "... seismic waves (1) that originate and ricochet, (2) which travel...". The use of two different relative pronouns ("that" and "which") and the lack of an "and" to link the two modifiers makes this structure confusing, at best.

So instead of looking at individual grammar points in a bubble to figure out which "rule" (B) violates the most, just recognize that the logical meaning is much clearer in choice (C).

Grammar issues are, at heart, about clarity and logic. So when comparing two choices, you always want to think about meaning. Do the differences between the two options impact the meaning? Is the meaning more clear/logical/reasonable in one option?

For more on that, check out the our SC guide for beginners, if you haven't already.

I hope that helps!

Hi everyone, the verb after "which" is actually plural (travel instead of travels); therefore, shouldn't this imply that we are talking about seismic waves, the only plural subject in this entire sentence? So choice B would technically make sense? Thanks!

Hello, jiaxin. I would not eliminate (B) on the grounds of which travel, but instead because of the comma preceding and. Compare (B) and (C):

To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, most rapidly traveling through cold, dense regions and slower through hotter rocks.

(B) interior, which travel most rapidly through cold, dense regions, and more slowly
(C) interior, traveling most rapidly through cold, dense regions and more slowly

In the sentence at hand, cold, dense is acting as a coordinate adjective to modify regions. The comma is necessary because the sentence could just as easily reverse the order of the adjectives, as in, dense, cold regions. If you follow the shell of the sentence with each answer choice, you get a comma that cannot be justified in (B), since and is just acting to join two adverbs that describe how waves travel, A and B, rather than introduce the final item in a list or join two independent clauses. Consider:

1) Geologists use a network of seismometers to chart seismic waves, which travel most rapidly through cold, dense regions, and more slowly through hotter rocks.
2) Geologists use a network of seismometers to chart seismic waves, traveling most rapidly through cold, dense regions and more slowly through hotter rocks.

Although I have seen people place a comma in the slot I am drawing attention to in (B), I have NOT seen such usage in a correct SC answer on the GMAT™. I hope that helps clarify any lingering doubts you may have harbored; if not, I would be happy to discuss the question further.

Good luck with your studies.

- Andrew

Dear sayantanc2k

The rule you told in the question
Wrong: I play and I sing
Right: I play, and I sing
Right: I play and sing.

is not complying to this below question can you please help

https://gmatclub.com/forum/many-states- ... 05883.html

RAHUL_GMAT I addressed this in your other post, but the short version is that this is not a rule. E does not convey the meaning well, but there's nothing grammatically wrong with saying "that originate and ricochet . . . . and that travel," as long as there is a reason not to put all three terms into a simple list. For the record, we can also say "I play and I sing."

Let's go through each answer:

(A) To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, most rapidly traveling through cold, dense regions and slower through hotter rocks.
ELIMINATE. Most rapidly is not parallel with slower.

(B)To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, which travel most rapidly through cold, dense regions, and more slowly through hotter rocks
ELIMINATE. Which is referring back to interior. So the interior travel most rapidly? Doesn't make sense.

(C)To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, traveling most rapidly through cold, dense regions and more slowly through hotter rocks
KEEP IT. -ING Modifier is referring back to waves. Most rapidly and more slowly are parallel. You could say that Traveling is referring to geologists use, BUT is important to notice that -ING modifiers modify the PRIOR action which is seismic waves that .... The main sentence of the prompt has a main noun (geologists), main verb (use), object (seismic waves), but likewise has embedded a second clause which is joint by THAT, so as mentioned before TRAVELING will refer back to the closest action.

(D)To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior and most rapidly travel through cold, dense regions, and slower through hotter rocks
ELIMINATE. Have the same problem as A (Which is referring to its interior). Also we have a conjunction between interior and travel that doesn't make sense. Most rapidly is not parallel with slower.

(E) To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior and that travel most rapidly through cold, dense regions and slower through hotter rocks
ELIMINATE. You could argue that "that travel" is referring back to seismic waves, because there is a parallelism structure between originate and travel. The problem with this answer is that most rapidly is not parallel with slower.

Why does C's
"traveling most rapidly through cold, dense regions and more slowly"
not modify the entire preceding clause
"geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior"

Why is it that "traveling most rapidly" is only modifying the seismic waves piece?
I eliminated C because "geologists use a network..traveling most rapidly.." is obviously illogical.

Yeah fireagablast, but the immediate preceding clause is:

that (seismic waves) originate in the earth's crust and ricochet around its interior.

So, seismic waves is the subject of the immediate preceding clause. It obviously makes sense to say:

seismic waves originate in the earth's crust and ricochet around its interior, traveling most rapidly...

From what I have seen, there is some flexibility in terms of what such participial phrases (traveling most rapidly) modify: they can either modify the immediate preceding clause or the main clause, whichever makes sense.

I suppose then i'm confused how the clauses are being split in this case.
Why is the statement not one single clause and instead of two seperate clauses?

With C, the sentence is:

To map Earth's interior, geologists use a network of seismometers to chart seismic waves that originate in the earth's crust and ricochet around its interior, traveling most rapidly through cold, dense regions and more slowly through hotter rocks.

The structure of this sentence is:

To map Earth's interior
- Introductory infinitive phrase

Geologists use a network of seismometers to chart seismic waves
- Main (Independent) Clause

that originate in the earth's crust and ricochet around its interior
- Relative (Dependent) Clause

traveling most rapidly through cold, dense regions and more slowly through hotter rocks
- Participial phrase

You can watch our video on Clauses:



You can also watch our video on on Independent & Dependent Clauses



p.s. Our book EducationAisle Sentence Correction Nirvana discusses Phrases & Clauses, their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

EducationAisle VeritasKarishma GMATNinja

Why is B incorrect? Why can't which refer to waves? I think it can.


He has a room full of chocolates, which is on ground floor.

Here which is referring "room."

Thanks!

Hi Ashmit, waves is way far from which in B; in fact, interior and curst are way closer to which, than waves is. Remember which almost always modifies the nearest grammatically eligible word.


Correct. Notice that the presence of is in your sentence mandates that which must modify a singular noun. Since chocolates is plural, which cannot modify chocolates here.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses modifier issue of "which", their application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

Alright got your point. However, don't you think "which" wouldn't make sense with interior or curst? Because interior or crust can't travel.


We've seen a lot of cases where which or that has two antecedents but logically they would refer to only one. Now, my point is we only see logical antecedents in GMAT right? Because it is said that GMAT is not a grammar test.