The Acoma and Hopi are probably the two oldest surviving Pueblo commun

Hi yt770, there is correlation between the participial phrase (both dating back...) and the previous clause.

The clause states that the Acoma and Hopi are probably the two oldest surviving Pueblo communities; subsequently, the participial phrase elaborates to what extent these communities are old: both date back at least a thousand years.

On the other hand, had the sentence been (say):

The Acoma and Hopi considered children born into the mother's clan, both dating back at least a thousand years.

In this sentence, there is indeed no correlation between the clause and the participial phrase. Hence, use of participial phrase would be incorrect here.

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

This question is based on Modifiers and Construction.

In Option B, the present perfect tense “have dated” is incorrect because there is no connection established between the past and the present in the sentence. The present perfect tense indicates that till the present, the communities have dated back at least a thousand years but this fact may change in the future. The meaning thus conveyed is illogical. So, Option B can be eliminated.

In Option C also, the present perfect tense is inappropriate. Furthermore, the conjunction ‘and’ in Option C implies that dating back is an action done by the two communities. Since this meaning is illogical, Option C can also be eliminated.

Option D is incomplete. The conjunction ‘and’ should be followed by a clause as the coordinating conjunction joins a clause to a clause and a phrase to a phrase. So, Option D can also be eliminated.

In Option E, the plural verb ‘date’ does not agree with the singular subject ‘each’. So, Option E can also be eliminated.

The participle ‘dating’ describes how the communities are probably the two oldest surviving Pueblo communities. The use of the modifier in Option A avoids the errors in the other options. Therefore, A is the most appropriate option.

Jayanthi Kumar.

@egmat,@gmat ninja. There are many answers saying the present perfect tense cannot be used in option C. Can you guys please explain

The issue is more with the logic than with the grammar.

I could write, "The ancient scroll has been dated at x," because it's not unreasonable for a scroll to have been studied in the past and to continue to be studied into the present. So the present perfect isn't really a problem.

But if I begin a sentence with "The ancient scroll has dated..." I'm making sound as though this ancient scroll was either assessing the date of another scroll or going on dates with other scrolls! An interesting idea for a wacky cartoon, but not a terribly logical sentence on the GMAT.

Same deal here: (C) kind of makes it sound as though the communities are going on dates. Kinda sexy, but also kinda nonsense.

I hope that helps!

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