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

I will try:
Subject :The Acoma and Hopi
They are probably the oldest survivng communities.

B and C change the context as if both communities do not exist any more.
D uses conjuction 'and' unnecessarly, which makes sentence too lenthy.
E is wordy.

Between A and D,
A uses both correctly to explain collective noun.

Let me help you rule out D. Notice "and" in choice D, "and" entails a parallelism here. However, the follwoing part of "and" doesn't go along with the struture of main clause. ( Choice D uses "dating" rather than "dates".

that's not actually a split; if you were to replace "both" with "each" in the correct answer, you would have another correct answer.

the problems actually lie elsewhere.
(c) and (d) are incorrect because of the word "and"; the sentence is not presenting two separate, independent facts, so "and" is inappropriate as a conjunction.

(b) and (c) are incorrect because of the tense used; "has dated" implies that this is not the case anymore. (this particular construction really only makes sense in the present tense -- or as an -ing modifier attached to a present-tense clause, since -ing modifiers adopt the tense of the clause to which they are attached.)

(e) has subject-verb disagreement ("each one of which" must be singular).

(d) uses complete sentence + comma + "and", a conjunction that should be followed by another independent clause. since "dating" isn't a verb, that second half is a fragment.

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

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").

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

Why "has dated" (present perfect) "implies that is not case any more"? For me, present perfect expresses an action that is still going (just as our case)

Thank you!

"present perfect = still going" is generally restricted to sentences in which the actual timeframe is given.
for instance:
i have had the flu --> by default, this means that i have had the flu at some time in the past (and that this is somehow relevant to the current conversation).
i have had the flu for the last two weeks --> this is "still going".

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes

Hi Ron,

I have a question of present perfect tense.

Freqeuntly I heard that "some studies have shown blah, blah, and even some articles of ny times say" ** evidence has suggested blah, blah"

My question is if present Perfect Tense is used here, then does that mean the studies NOW no long show blah, blah, and the evidence NOW no longer suggests blah , blah ?

I assume that the writers reference the studies and evidence to support their argument( currect topic of discussion, relevance to the present), and that if the studies or evidence no Longer show or suggest blah blah at the moment the writers made the argument, then their arguments are weakened rather than strenthened.

Thanks.

Hi yuanfeng.ma,

Tenses used in sentences rely a lot on the context in which they are used. It will be very difficult to comment on why those articles used present perfect without actually seeing the whole article.

On the GMAT, you will be given one sentence and one sentence only. If the meaning justifies the use of perfect tenses, then its ok to use them. Otherwise use simple tenses. This is a very broad advice but the SC book, chapter 7 does a fairly good job in detailing when its OK to use perfect tenses on GMAT

Regards

Sunil

Hi Sunil,

Thanks again.

I just did a quick search of " evidence has suggested" on NY times, and Then I got tens of hits--- see below URL.


http://query.nytimes.com/search/sitesearch?query=%22evidence+has+suggested%22&more=date_all

actually the seach has relevance to OG12, # 128, explanation says evidence has suggested -- present perfect is inaccurate.

I am not convinced by the explanation.

Can you enlighten me?
Thanks

Hi yuanfeng.ma,

Unfortunately, OG questions cannot be discussed on these forums. I will not be able to help you with your query that way.

Please ask a question based on the rule that is being tested without referring to the question and then we can proceed.

Thanks

Sunil

Hi yuanfeng,
This is why you should NEVER look at outside sources when trying to study SC problems. The GMAT has its own grammar rules, and i see the New York Times violating them all the time. This does not make the GMAT wrong. Remember, the GMAT is always right, at least if you want to score well on the test.. :)

_________________
Tim Sanders
Manhattan GMAT Instructor

GMAT grammar rule is separate from and maybe better than other rules of grammar, and of course, separate from grammar rules from other source.

RON,
present perfect makes us troubles on GMAT. Ron, could you please tell us all the cases you know, in which present perfect is used. Pls, give us example for each case.

waiting for you, Ron.

if you're just doing a search and then looking at the total number of hits, then the result is absolutely meaningless, because you have no context for any of those hits. verb tenses are 100% determined by context, so, hopefully, the shortcomings of considering them outside of context are rather obvious.

take a look at the first few hits -- most of them are talking about trends in past evidence, a totally different context.

_________________
Being well-dressed gives a feeling of inward tranquillity [that] religion is powerless to bestow.
C.F. Forbes