One of the earliest known birds with a beak and contour feathers, Confuciusornis sanctus, with large clawlike “thumbs” on its wings, which probably helped them to climb up to a launching position for flight.
A. with large clawlike “thumbs” on its wings, which probably helped them to
B. with large clawlike “thumbs” on their wings, which probably helped it to
C. had large clawlike “thumbs” on its wings, which probably helped them
D. had large clawlike “thumbs” on its wings, probably to help it
E. had large clawlike “thumbs” on their wings, probably to help it

This is GMATPREP question. What is wrong with answer "E" and why answer "D" is correct?

Is it possible to answer this question or is this a banned source too ??



Speaking of banned sources, are there any more sources out there that are still not considered as a "black list" and can be discussed on this forum.

I truly believe that Stacy and Ron are the best tutors any student preparing for GMAT can have. I personally have improved my score on SC from a paltry 30-32% to an approximate 75+% hit ratio now. Have probably gone through each and every post of the Verbal(SC) question on this forum and diligently prepared notes etc. It truly helped me grasp the concepts etc.....and now I am digressing...:-)

It is real sad to see that we cannot discuss any more questions on this forum.....

In any event thank you Stacy & Ron.....you guys rock!!!!

nah, we can answer these; the OP just happened to post an enormous number of problems on the same day, so we ignored them over a certain maximum # so that we could allot some of our attention to other posters' material.

the Stickies at the top of each thread contain a list of banned sources. if your source isn't in the list, you can assume that it's ok.

--

breakdown of the above problem:
(a), (b)
these aren't sentences at all, since neither of them has a main verb.

(c), (e)
inconsistent pronouns: in (c) 'it' suddenly changes to 'them', and in (e) 'them' suddenly changes to 'it'.
in fact, you can eliminate ALL of the wrong answer choices on this pronoun issue alone; note that choice (d) is the only one of the five that contains consistent pronouns.

note that the pronouns MUST be singular, anyway, because they refer to 'one of the earliest known birds...' so even if you had an answer choice with both 'their' and 'them', it'd still be wrong.

Thanks...

All question seem so obvious after one sees the explanation..... :)

In choice D, is "probably to help it" a adv or adj?
if it is an adv, " confuciusornis sanctus" would be the logic subject of "help"
shouldn't it be "probably to help itself" rather than "probably to help it" in that case?

[deleted - contains a question from OG, which is a banned source for reasons related to copyright]

Confuciusornis sanctus,

Waht does this comma means
Isn't it should be without comma and is the use of comma correct here

first, and most importantly, DO NOT QUESTION OFFICIALLY CORRECT ANSWERS. OFFICIALLY CORRECT ANSWERS ARE ALWAYS 100% CORRECT, according to GMAC (whose opinion is the only opinion that matters).

if you are surprised by the comma, then:
the WRONG question for you to ask is --> "is the comma correct?" (of course it's correct; it's in an officially correct answer.)
the RIGHT question to ask is --> "WHY is that comma correct? i want to learn this new fact."

in this case, the given scientific name (Confuciusornis sanctus) is just an additional, disposable fact, and so is written as an appositive modifier.
any modifier that's present in the middle of a sentence must either be set off by commas on BOTH sides, or be set off by NO commas. it's impossible to place a comma on only one side of a modifier, unless that modifier begins or ends the sentence.

Hi, Ron.
I still can't figure out why the comma is put before an infinitive modifier(probably to help).
Without mention of the comma before probably to help , you just explained the comma before the appositive modifier(Confuciusornis sanctus) and the comma after the appositive modifier.
I'm really confused. Please help.
Thanks.

that's an issue of “essential vs. nonessential modifier".
NOTE: i've never seen this issue directly tested, so it's not important for you to be able to distinguish between the two -- the only thing that's important is for you to realize that both are ok, under certain circumstances

an "essential" modifier (which is NOT set off by commas) is a modifier that actually narrows or specifies the noun/action to which it's attached.
for instance:
our top student whose score fell below 50 received a consolation prize.
--> this doesn't refer to the top student among all of our students; this only refers to the top student among those whose scores fell below 50 points. therefore, we need the essential modifier (no commas) to narrow "our students" to "students whose score fell below 50".

a "nonessential" modifier (which IS set off by commas) is a modifier that does not narrow or specify the nouns/action to any greater degree than does the rest of the sentence; it merely provides more information about that noun/action.
for instance:
our top student, whose score fell below 50, received a consolation prize.
--> here, we are actually talking about our top student. the meaning of the sentence is that all of our students' scores were below 50, but at least our top student received a consolation prize.

in this case, the nonessential modifier (with the comma) makes more sense; the following words are just a little bit of color commentary speculating on the possible purpose of this anatomy. they don't narrow anything, so an essential modifier would be inappropriate.

Hi Ron,

What is the function of Comma+ infinitive in D?

IN OG12, question 30, regarding Choice E, the explaination said infinitive should not follow a comma if the infinitive is a modifier.

How does that question from this one in the usage of Comma+ infinitive ?

Thanks in advance

Hi yuanfeng.ma,

Unfortunately we cannot discuss OG questions on these forums.

In this particular question, the modifier starts with "probably" which is an adverb. So the part after the comma: "probably to..." becomes an adverbial modifier.

Adverbial modifiers modify the verb or action in the preceding clause:

....Confuciusornis sanctus had large ....., probably to help

Regards

Sunil

Hi Sunil,
Thanks a lot.

I see---Then it's comma+adverb+infinitive rather than comma+infinitive.

By the way, are you a manhattan gmat staff?

Hey,

No no, I am far from it, just a student like you. :) Not as good as those guys.

Manhattan Staff have red colored usernames

Regards

Sunil