The Anasazi settlements at Chaco Canyon were built on a spectacular sc

Hi GMAT exports,

I am confused about the sentence structure of this question. If the modifiers, "of up to 600 rooms each" and "connected by a complex regional system of roads" both modify "structure", why there is no conjunction word "and". Should the absence of "and" be a parallelism error for choice B? Can someone please let me know if "and" is always required in a list?

Dear bubblehead0922,

I'm happy to respond.

Here is version (B), the OA:
The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, connected by a complex regional system of roads.
This is 100% correct as is.

A list is a series of discrete elements. For a list structure, the elements are in parallel and of course we typically would have "and" or "or" joining the elements. That is not what is happening in this sentence. This sentence did not attempt to create a list and do the job poorly. Instead, it was doing something else.

There are several other patterns in language beside listing. One pattern is the parenthetical remark. A parenthetical remark, sometimes called an "aside," is an extra piece of information that the speaker throws in. It typically disrupts the flow of the sentence, and often is set off on each side either by commas or by dashes (em-dashes).

In this sentence, the parenthetical remark is "of up to 600 rooms each." Notice that we could remove this remark and the sentence would still be perfectly fine. The author could have chosen to write this as the following:
The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures—of up to 600 rooms each—connected by a complex regional system of roads.
That version sets the parenthetical remark off in em-dashes. This version is not as good: we set off a parenthetical remark in em-dashes when it's logically further from the sentence, a real interruption to the flow of thought. Here, the parenthetical remark is still very much on topic, so setting it off between a pair of commas is fine.

This is NOT parallelism. This is a different way of positioning a pair of complex modifiers.

My friend, there's no complete list anywhere of all the ways that language can be used. It's impossible to get to SC mastery by learning some mythical "complete set" of rules. You have to learn the "feel" of the language, and the only way to develop that is to cultivate a habit of reading. See:
How to Improve Your GMAT Verbal Score

Does all this make sense?
Mike

My Answer B (Awaiting OA)

The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.

A. with more than 75 carefully engineered structures, of up to 600 rooms each, were -"were" is not required. we just need to say that "Canyon had more than 75 structures connected by system of roads."
B. with more than 75 carefully engineered structures, of up to 600 rooms each, -Correct
C. of more than 75 carefully engineered structures of up to 600 rooms, each that had been -"spectacular scale of more than 75 structures" doesn't seem correct. The Chaco Canyon was built on a very large scale consisting of more than 75 structures. Thus, the opening words of this option aren't correct. Also, this option is depicting that each of 600 rooms were interconnected by a system of roads; this thought is nonsensical.
D. of more than 75 carefully engineered structures of up to 600 rooms and with each -Opening words of this option are wrong as per the explanation in option C.
E. of more than 75 carefully engineered structures of up to 600 rooms each had been -Opening words of this option are wrong as per the explanation in option C.

The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.

A. with more than 75 carefully engineered structures, of up to 600 rooms each, were --- it is clear that this simple sentence is riddled with two verbs namely 'were built' and 'were connected' without a proper conjugation. This is double verbing and out

B. with more than 75 carefully engineered structures, of up to 600 rooms each, ---Now that the double verbing is gone, let us come back to this a while later.

C. of more than 75 carefully engineered structures of up to 600 rooms, each that had been -- it is absurd to say that the 75 structures had been interconnected before they were constructed. Therefore this is out.

D. of more than 75 carefully engineered structures of up to 600 rooms and with each --- comma plus with each is a phrase. This not parallel with the previous IC and We may call it either unparallel or the second part a fragment

E. of more than 75 carefully engineered structures of up to 600 rooms each had been-- here is a fused sentence, the first with were constructed, and the second with had been connected( we already know 'had been' is wrong)

Now let's go back to B, the structure is a simple sentence with an underlined 'comma plus ed modifier' at the end. perfect foil

Firstly, thank you for your explanation, I really appriciate that. But i have question ralted to Subgroup question.
For this question, the OG explain in answer C that " The comma preceding each make each a subject, but is has no verb, since that is the subject of had been connected". BUt what if it could be the SUBGROUP MODIFIER as the sentence following in Manhattan:
This model explains all known subatomic particles, SOME only recently discovered.
or "This model explains all known subatomic particles, SOME OF THEM only recently discovered"
I acknowledge that answer C makes no sense but the official explanation make me confused.
Please clarify!

Yeah... I have no idea what the OG is talking about there. Keep in mind that the people who wrote the OG explanations are NOT the same people that wrote the questions. In most cases, the OG questions were produced years -- or even decades -- before they appeared publicly in the OGs, so whoever writes the explanations often doesn't know what the question-writer intended. And sometimes you just get incoherent messes as a result.

I think you might also be asking whether it's possible to have a subgroup modifier -- or an absolute phrase -- beginning with "each." Sure, that's entirely possible in theory, it's just that the meaning doesn't make sense in this case. Here's an example that might help: https://gmatclub.com/forum/qotd-naked-m ... 39472.html.

But don't worry too much about those OG explanations if you don't find them helpful. Some of them are awesome. Others are putrid.

Ron's answer

choice a is a run-on - it tries to have two main verbs without using any sort of subordinating element. if you take out modifiers, adjectives, etc., you're left with the following: the settlements were built with structures were connected. that's bad.

choice b is correct: it uses a nonessential modifier set off by commas ('of up to 600 rooms each'), which, if eliminated, yields the intact and legitimate sentence ...carefully engineered structures, connected by... (with another nonessential modifier).

choice c:
- 'scale of' doesn't make sense
- you can't say 'each that had...' (can't follow 'each' with a relative pronoun - if you're going to use a relative pronoun, it has to come directly after the thing it's trying to modify)
- no justification for using the past perfect ('had been') - that verb, if there's a verb there at all, should be in the simple past (the same tense as everything else in the sentence, because everything described in the sentence is contemporaneous)
- it doesn't make sense to use 'each' AFTER the comma, because it's not true that each structure was connected with a road system. instead, the road system connected all of the structures with each other, which is nowhere close to the same thing. (having 'each' BEFORE the comma makes sense, because it's actually true that each of the structures comprised up to 600 rooms.)
analogy:
the USA comprises 50 states, each of which is united by a federal government --> wrong (the implication is that each state has its own federal government)
the USA comprises 50 states, all of which are united by a federal government --> correct
the USA comprises 50 states, (all) united by a federal government --> correct, whether you have 'all' or not

choice d:
- 'scale of' doesn't make sense
- the use of AND sets up ostensible parallelism, but the two structures given aren't parallel (one starts with of and the other with with)

choice e is also a run-on sentence (you'll see this if you reduce it to its 'skeleton', a la choice a)

OA (B), has "connected" modifying each. Isn't is wrong for an ed-modifier? Or can an ed-modifier modify something even if it has a descriptive clause in between?

In choice (A), "connected..." modifies "structures". We have some additional info about the structures separated by commas ("of up to 600 rooms each"). But if we remove that non-essential info (and strip out some modifiers), we are left with, "The settlements were built on a spectacular scale with more than 75 structures connected by a complex regional system of roads."

We obviously can't connect rooms within a structure with a complex regional system of roads. So even when we add the comma-separated phrase back in, it is still clear that "connected" modifies "structures".

Now, that doesn't mean you should look at this specific sentence and make up some broad rule about ed-modifiers and descriptive clauses. Remember that there are very few concrete, black and white "rules" that you can blindly apply to GMAT SC.

Just because a construction works in one correct answer choice doesn't mean that construction is always correct. And just because a construction doesn't work in an incorrect answer choice doesn't mean that it's always wrong.

I hope that helps a bit!

EMPOWERgmatVerbal I have been using your strategy for SC. Stuck on this one, can I ask your help?

Thanks!

Thanks for the question eldvin! Let's tackle this one using our method of searching for differences, then narrowing down choices from there:

The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.


A. with more than 75 carefully engineered structures, of up to 600 rooms each, were

B. with more than 75 carefully engineered structures, of up to 600 rooms each,

C. of more than 75 carefully engineered structures of up to 600 rooms, each that had been

D. of more than 75 carefully engineered structures of up to 600 rooms and with each

E. of more than 75 carefully engineered structures of up to 600 rooms each had been

After a quick glance over the options, we have 2 main areas we can focus on:

1. with vs. of (Idioms)
2. their endings (Construction & Modifiers)

Since #1 on our list is an either/or split, let's start there. This is an idiom issue. When discussing the components of a creation, we use "built with" or "made of." The phrase "built of" isn't idiomatically correct. So let's eliminate any that misuse idioms:

A. with more than 75 carefully engineered structures, of up to 600 rooms each, were
B. with more than 75 carefully engineered structures, of up to 600 rooms each,
C. of more than 75 carefully engineered structures of up to 600 rooms, each that had been
D. of more than 75 carefully engineered structures of up to 600 rooms and with each
E. of more than 75 carefully engineered structures of up to 600 rooms each had been

We can eliminate options C, D, & E because they don't follow the correct idiom format of "built with." Now that we have it narrowed down to only 2 options, let's tackle #2 on our list and look for any problems we can find. To make problems easier to spot, let's add in the non-underlined sections:

A. The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, were connected by a complex regional system of roads.

This is INCORRECT because the added commas make the phrase "of up to 600 rooms each" a non-essential clause. If we take that clause out (because all non-essential clauses are optional), what we have left should still work as a complete sentence. In this case, if we remove that phrase, it doesn't work on its own. So let's rule this one out.

B. The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, connected by a complex regional system of roads.

This is CORRECT! If we take out the non-essential clause "of up to 600 rooms each," the sentence still makes sense when read without it!

There you have it - option B is our winner!

I hope that helped eldvin! Make sure to tag us if you have any other questions!

answer A sounds to me like the Anasazi settlements were built using structures of up to 600 rooms each, this obviously is not the intended meaning. Can anyone explain to me why my interpretation of the answer isn't correct?

Let's take a look at an example where "with" means "using":

• "MacGyver dug a trench with a toothpick." - This seems okay. Then again, if the intended meaning is "using," why not just write "using"? As written, can't the reader interpret this to mean that the trench somehow contains or consists of a toothpick??
• "MacGyver dug a trench using a toothpick." - I think this is better, since the meaning is clear and unambiguous.

Can "with" mean "using"? Sure, but that usage is often a bit confusing. Back to choices (A) and (B): it's obvious that the settlements were not built using "more than 75 carefully engineered structures, of up to 600 rooms each," so the "with" seems reasonable.

More importantly, questioning whether "with" means "using" here is certainly not a strong enough reason to eliminate (A) and (B). By using process of elimination (as described in this post), you'll see that (B) is the best choice.

I hope that helps!

"Scale of" cant be correct. The scale is not consisting of engineered structures. It was simply built on a spectacular scale, which is obvious when we look at the overwhelming structures.

Posted from my mobile device

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that the Anasazi settlements at Chaco Canyon were built on a spectacular scale and had more than 75 carefully engineered structures, and these structures had 600 rooms each and were connected by a complex regional system of roads.

Concepts tested here: Meaning + Tenses + Grammatical Construction

• In a “noun + comma + phrase” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• If a list contains only two elements, they must be joined by a conjunction.
• The simple past tense is used to refer to events that concluded in the past.
• The past perfect tense (marked by the use of the helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".

A: This answer choice incorrectly uses a comma to join two elements in a list - "were built..." and "were connected..."; please remember, if a list contains only two elements, they must be joined by a conjunction.

B: Correct. The sentence formed by this answer choice uses the phrase "were built on a spectacular scale with more than 75 carefully engineered structures", conveying the intended meaning - that the Anasazi settlements at Chaco Canyon were built on a spectacular scale and had more than 75 carefully engineered structures. Moreover, Option B correctly modifies "75 carefully engineered structures" with "connected by a complex regional system of roads", conveying the intended meaning - that the structures themselves were connected by a regional system of roads. Further, Option B avoids the tense error seen in Options C and E, as it uses the past participle "connected" rather than an active verb. Additionally, Option B avoids the grammatical construction error seen in Option A, as it presents no elements in a list.

C: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "were built on a spectacular scale of more than 75 carefully engineered structures"; the construction of this phrase leads to an incoherent meaning; the intended meaning is that the Anasazi settlements at Chaco Canyon were built on a spectacular scale and had more than 75 carefully engineered structures. Moreover, Option C incorrectly modifies "600 rooms" with "each that had been...roads", illogically implying that each of the 600 rooms of the 75 structures was connected by a regional system of roads; the intended meaning is that the structures themselves were connected by a regional system of roads; please remember, in a “noun + comma + phrase” construction, the phrase must correctly modify the noun. Further, Option C incorrectly uses the past perfect tense verb "had been connected" to refer to an event that concluded in the past; please remember, the simple past tense is used to refer to events that concluded in the past, and the past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".

D: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "were built on a spectacular scale of more than 75 carefully engineered structures"; the construction of this phrase leads to an incoherent meaning; the intended meaning is that the Anasazi settlements at Chaco Canyon were built on a spectacular scale and had more than 75 carefully engineered structures. Moreover, Option D further alters the meaning through the phrase "600 rooms and with each"; the construction of this phrase illogically implies that each of the 600 rooms of the 75 structures was connected by a regional system of roads; the intended meaning is that the structures themselves were connected by a regional system of roads.

E: The sentence formed by this answer choice alters the meaning of the sentence through the phrase "were built on a spectacular scale of more than 75 carefully engineered structures"; the construction of this phrase leads to an incoherent meaning; the intended meaning is that the Anasazi settlements at Chaco Canyon were built on a spectacular scale and had more than 75 carefully engineered structures. Moreover, Option E further alters the meaning through the phrase "each had been"; the construction of this phrase illogically implies that each of the 600 rooms of the 75 structures was connected by a regional system of roads; the intended meaning is that the structures themselves were connected by a regional system of roads. Further, Option E incorrectly uses the past perfect tense verb "had been connected" to refer to an event that concluded in the past; please remember, the simple past tense is used to refer to events that concluded in the past, and the past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".

Hence, B is the best answer choice.

ExpertsGlobal5 hello expert, I went through your explanation and thanks for your input, but I’m confused between B and D. As this is a SC question(only one sentence and there is no context), how can we know it’s intended meaning? Honestly I think the meaning in D(“each of the 600 rooms of the 75 structures was connected by a regional system of roads”) also make sense to me.
Besides, in B, there are 3 mordifiers, and I think there should be an “and” before the last modifier(“connected by...roads”). Hope you help and thanks in advance.

Hello Mavisdu1017,

We hope this finds you well.

To answer your query, we can say that Option D conveys an incorrect meaning because it implies that the rooms within the structures were connected by a regional system of roads. Logically, it makes no sense that rooms inside a building are connected by roads; we would not say that "There is a road connecting the lobbies of the two hotels." because, logically, the road must end where the building begins.

We hope this helps.
All the best!
Experts' Global Team

I am sorry for my silly question (I think).

I didn't understand the meaning of "of up to 600 rooms each". I understand that it is a non-essential modifier, but i never seen any such structure.
Please someone help me understand the meaning and structure of this modifier.

Thanks in advance.

Posted from my mobile device