The Acoma and Hopi are probably the two

[RonPurewal]

Type 2/
If it's an ongoing state verb, then "has/have VERBed" without an explicit time period means ...
... it's happened before,
... it's not happening now.

E.g.,
I have lived in Florida.
This implies that I no longer live in Florida. If I still live there now, I'll write I live in Florida.

----- BUT -----

If, for this kind of verb, "has/have VERBed" is used with a time duration, then ...
... it has happened for that duration up to now;
... it may still be happening, or it may just have ended.

E.g.,
I have lived in Florida for twenty years. (written in 2014)
This means I've lived in Florida for the last twenty years (= 1994-2014).
I might still live there.
I may be moving right now.

[RonPurewal]

Regarding the problem you're asking about"”

Dating objects (= evaluating their age) is a point action, like graduating from high school.
So, "have been dated" means that it happened sometime"”any time"”and that it's relevant to the present. Exactly what's necessary here.

[1009918171]

Thanks a lot for the great explanations!

[RonPurewal]

You're welcome.

[thanghnvn]

The Acoma and Hopi are probably the two oldest surviving Pueblo communities, both dating back at least a thousand years.
A. both dating
B. both of which have dated
C. and each has dated
D. and each one dating
E. each one of which date
from prep
OA is A

can you tell me "both" vs."each" as a split ?
please explain why each choice is correct / incorrect

the most important point is how to eliminate B.

in B, "both of which ..." modify the "communities" and is purely adjectival. This modification is not what we need. in A, "both dating..." modifies the main clause, showing the reason for main clause. note that "dating" refers to "communities" and at the same time, modifies the main clause. some grammar books write that this phrase is both adjectival and adverbial. This modification is what we need.

am I correct?

[RonPurewal]

The Acoma and Hopi are probably the two oldest surviving Pueblo communities, both dating back at least a thousand years.
A. both dating
B. both of which have dated
C. and each has dated
D. and each one dating
E. each one of which date
from prep
OA is A

can you tell me "both" vs."each" as a split ?
please explain why each choice is correct / incorrect

the most important point is how to eliminate B.

in B, "both of which ..." modify the "communities" and is purely adjectival. This modification is not what we need. in A, "both dating..." modifies the main clause, showing the reason for main clause. note that "dating" refers to "communities" and at the same time, modifies the main clause. some grammar books write that this phrase is both adjectival and adverbial. This modification is what we need.

am I correct?

I don't know the grammar terms you're using, so I can't evaluate that part of what you wrote.
The message, though, seems accurate: You want a construction that reflects the close relationship between "are the two oldest communities" and "are xxxxx number of years old".

[thanghnvn]

The Acoma and Hopi are probably the two oldest surviving Pueblo communities, both dating back at least a thousand years.
A. both dating
B. both of which have dated
C. and each has dated
D. and each one dating
E. each one of which date
from prep

what I want to say is that there is a big difference between A and B. this difference is an important and hard point.

in A, "both dating" modifies the main clause though this phrase refers to the "communities". we can think that "both dating..." is both adjective and adverb. this kind of phrase is very popular in writen english. though some persons think this kind of phrase is adjective phrase, it is not.

all of us know the pattern "comma+doing". this phrase is similar to "both dating..." in our sentence

I learn gmat, making my thingking better.

"making my..." refers to "I" and modifies the main clause. like choice A, this phrase refers to a specific noun and modifies the whole main clause.

the difference between choice A and the sentence " I learn gmat..." is that in choice A, "both dating" refer to "communities" which is not subject of the main clause while in the sentence "I learn gmat..." , "making my..." refers to the subject of main clause. the similarity between the two phrases is that they refer to a noun and in parallel, modify the main clause.



in B, "both of which have..." modifies only the "communities" . the fuction of this phrase is quite difference. this phrase is like adjective.

the intended meaning is the meaning in choice A. we need an adverb phrase to show the reason for the main clause.

[RonPurewal]

Do you have a question?

If so, please clarify. Thanks.

[eggpain24]

Hi，Ron， I got a problem here about the usage of “each”

in choice C & D

could “each” OR “each one” possibly refer to either “Acoma” or “Hopi”

I am not sure about whether "each" is legitimately used here，because in non-underline part we get “ The Acoma and Hopi”（which is a compounded noun joint by and and should be regarded as one unit)

can you help me on this?

Thank you!

[jingjiaol257]

Hi Ron...
if we resolve the subject - verb problem of E
i.e. each one of which dates..., will it become right in this sentence?

Also if we have this modified version, is it better than A?

Please comment

that still wouldn't be ideal, since you would still have a "which" modifier after the comma. in those situations, you want the "which" modifier to be attached directly to the thing that it modifies; in this case, that would mean that "each of which" should be tagged directly onto "acoma and hopi".
the construction in choice (a), on the other hand, applies directly to the subject of the preceding clause -- and that's exactly what we want it to do (since "acoma and hopi" is the subject of the preceding clause).

also, there would be no need for "one" (i.e., just "each of which" is superior to "each one of which").

hi ron
i can't understand your explanation above well.can you tell me what the "which" modify in choice E after we resolve the subject - verb problem of E?
which modify the wrong things ?or which can modify the right thing but it is inferior to the construction in A?
Thanks!

[RonPurewal]

The placement of "which" here is mainly an issue of stylistics. It's a genuine issue, but it will never be the only thing tested in an answer choice. (Wrong answers are never problematic only in terms of style; any wrong answer will have at least one problem of mechanics and/or objective meaning.)

E.g.,

Ron, who is MGMAT's primary forum moderator, is almost 40 years old.
––> Good sentence.

Ron is MGMAT's primary forum moderator, who is almost 40 years old.
––> Arguably, this sentence isn't 100% wrong. But "who is almost 40 years old" should be attached to "Ron". It should not be attached to the job title——even if Ron is the only person holding that title——because that's not the point of the sentence.

Same problem with "each of which...". That modifier should be attached directly to "the Acoma and Hopi".
Attaching it where it's attached in choice E is a lot like attaching "who is almost 40" to Ron's job title, rather than to "Ron".

[RonPurewal]

MUCH MORE IMPORTANTLY ...

The only thing worth retaining about choice E is the subject-verb issue.

This is a clear-cut issue. It's very easy to find.

When choices contain stylistic issues or other subtleties, those elements are almost always present to distract you from much easier eliminations.

It's no coincidence that the "which" issue (which is MUCH too subtle to be worth worrying about) is paired with subject-verb agreement, which is probably the most straightforward error in the entire canon of GMAT SC.

If something is clearly a focal point, and other things are clearly distractions, don't get distracted by the distractions.

And definitely don't study the distractions, since that will come at the expense of the big stuff.

[RonPurewal]

The problem above tends to be most severe for people who have been studying SC for too long.

People don't want to hear this——it's a blow to the ego——but almost 100% of problems rely on one of the following 6 types of errors:
• Parallelism
• S-V agreement
• Pronoun problems
• Placement (when words are moved around)
• Choice between/among different kinds of modifiers
• Overall sentence integrity (is it a sentence? vs. a fragment/run-on)

There are some other semi-major things, such as VERY BASIC idioms, but most of those things don't demand active study.

When people have been studying SC for way too long——usually because they're chasing an elusive sense of "perfectly complete preparation" (there's no such thing, guys)——their brains become bored with the basics. That's when things go south, because you'll start to ignore the basics, instead concentrating on things that are actually written into the choices as distractions.

[RonPurewal]

And, in contemplating the list above, don't forget——"Meaning" is NOT separate from "grammar".

With the exception of S-V agreement and overall sentence integrity, which are mechanical issues, everything in SC——including the resolution of all the other "bullet points" above——ALWAYS depends on the intended meaning of the sentence.

Classifying "meaning" as separate from "grammar" is possibly the single worst mistake a GMAT student can commit. "Grammar" doesn't even exist without an intended meaning.

[JaneC643]

Hi, Ron

Just as mentioned before, in the choice B, "which" is too far from "the Acoma and Hopi", so it is inferior. But why the correct answer is right? I also think "both" is too far from "the Acoma and Hopi". Besides this, I am thinking whether such structure is called "absolute phrase"?

Thank you!