Since the 1930s aircraft manufacturers have tried to build airplanes

Hi omadangopal123, the portion after the comma is not an independent clause. It is (what's called) a resumptive modifier. You can do a Google search for this term, to know more about it.

The structure is:

Phrase (wings so smooth and so perfectly shaped) + Dependent clause (that the air passing over them would not become turbulent)

Grammatically, such structures function as phrases.

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

One ambiguity in the sentence is that it’s not clear what the modifier ‘shaped’ modifies; it can modify either ‘wings’ or ‘airplanes’. Even though I wouldn’t call this a major error in the sentence, it’s indeed a deficiency.

The second issue with the sentence is that both ‘smoothly’ and ‘perfectly’ modify ‘shaped’. It makes much more sense to say that the wings are smooth than to say that the wings are shaped smoothly.



A. wings, shaped so smoothly and perfectly
Incorrect. For the reasons mentioned above.

B. wings, wings so smooth and so perfectly shaped
Correct. Many people reject this option since “wings, wings” seems unacceptably awkward. However, “wings” after comma begins a Noun+Noun modifier (or an absolute phrase). This Noun+Noun modifier modifies “wings” before the comma. The meaning communicated here is that the wings are smooth and shaped perfectly. Thus, the meaning corrects the second problem of the original sentence.

C. wings that are shaped so smooth and perfect
Incorrect. Both issues present in the original sentence are present in this option as well. This option has an additional deterministic error that the adjectives “smooth” and “perfect” are used to modify the verb-ed modifier “shaped”. We need adverbs (“smoothly” and “perfectly”) to modify a verb-ed modifier.

D. wings, shaped in such a smooth and perfect manner
Incorrect. This option has both issues present in the original sentence.

E. wings, wings having been shaped smoothly and perfectly so
Incorrect. This option repeats the second issue of the original sentence. This option has an additional issue. “Having been shaped” is a perfect participle. Thus, it presents an action that happened earlier than another action. In this context, this means that the action of “shaping” happened before the action of “trying to build”. This is completely illogical.

GMATNinja VeritasKarishma

please tell why option A incorrect
and why B correct

saby1410

Option (A) says that the wings are smoothly shaped and perfectly shaped. Does that make sense? Think about it - what is a smooth shape? The surface of the wing can be smooth or rough but the shape? Even if you assume that they mean smooth edges etc, wouldn't that already be a part of "perfect shape"? Hence, (A) is not correct.

On the other hand, it makes sense that the wings are smooth and perfectly shaped to ensure that the air over them does not become turbulent. Hence (B) is correct.

One move the GMAT will make to increase clarity in a sentence is to repeat a noun so that we know exactly what is being modified. As discussed above, "shaped" could be read as modifying airplanes or wings. Repeating the needed noun makes the meaning unambiguous. You can see the same move in this question: https://gmatclub.com/forum/proponents-o ... 17516.html

One reason why A is wrong because

Since the 1930's aircraft manufacturers have tried to build airplanes with frictionless wings ----DC
, shaped so smoothly and perfectly that the air passing over them would not become turbulent.--Modifier

The Sentence structure of A is "DC,modifier" in which the long modifier "shaped so smoothly and perfectly that the air passing over them would not become turbulent" is "trying" to modify wings. Although the usage of this modifier is ambiguous as it can modify both airplanes or wings. Now, even if we consider the modifier is modifying the closest noun i.e. wings (which is also more logical), the "DC,modifier" is not a complete sentence.

Since 1930's aircraft manufacturers have tried to build airplanes with wings, (some description about wings)..... where is the rest of the story?

In Option B, even though the noun was repeated, the sentence structure is more clear and concise. (DC,IC)

Hi Antriksh, this is actually an Independent clause.

Thanks Sir. I understand it now. Somehow, when I read this sentence for the first time, it occurred to me as an incomplete thought therefore I was considering it as DC. I understand now that it's actually an IC.

Since the 1930's-----------Modifier modifying 'have tried'
aircraft manufacturers -------Noun
have tried ---------------------Verb
to build airplanes with frictionless wings ----infinitive/prepositional phrase
----------------------------------------------------------------------------
Over all IC as it is giving a complete thought that "since 1930s aircraft manufacturers tried to build the airplanes with friction less wings".

, shaped so smoothly and perfectly ---Ambiguous Modifier (wings/airplanes)
that the air passing over them would not become turbulent.(DC)
--------------------------------------------------------------------------
Over all a big modifier that is basically trying to modify Wings/Airplanes.

Overall structure "IC,verb-ed modifier".

Please correct me if I am wrong.

Would D be correct if there was no comma?

Yep..that's correct; by "verb-ed modifier", I am assuming you are referring to the past participial phrase (shaped so smoothly...).

Not sure if you read the entire thread. Meaning-wise, the issue with option D is similar to the issue with option A: these options basically state that wings are shaped in a smooth manner.

This is not very logical. Wings can be shaped in a perfect manner, but smooth is more a characteristic of the surface (and not of the shape).

GMATNinja
Can you please provide explanation for this question. I was confused between B and C.

Let's compare (B) and (C):

Check out the noun modifier in (C): "... that are shaped so smooth and perfect..." - does this modify "wings" or "airplanes"? Notice that it could technically modifier either one. (If you're wondering why it can modifier "airplanes," check out this article, particularly usage #4.

In (B), we don't have that ambiguity. The word "wings" is repeated, so we know without a doubt that "so smooth and so perfectly shaped" modifies "wings". That gives us one solid vote in favor of (B) over (C).

Also, "so smooth and perfect..." is trying to give us more information about how the wings are shaped -- so we'd actually want to use adverbs here (i.e. "smoothly and perfectly"), not adjectives ("smooth and perfect").

Lastly, notice that in (B), the wings are "so smooth," but in (C), the wings are "shaped so smooth..." -- what exactly does it mean to be "shaped so smooth(ly)"? Aren't we just trying to say that the wings are smooth? This is a minor point, but the modifier is more direct and clear in (B).

That gives you enough reason to pick (B) over (C)!

A- So smoothly and perfectly: so perfectly May be correct
B- S smooth and so — shaped followed by that – seems good
C- Same error like In A
D- B looks more convincing than F
E- Having been – wrong

Posted from my mobile device

One can also refer to Gmatclub Grammer book for this ?

Dear experts,

I can eliminate A C D and E but I am wondering that double so in C is acceptable :
"so smooth and so perfectly shaped that.. "

Presumably you're asking about the double "so" in choice (B)... and since that's our OA, we know it must be acceptable!

It's no problem to add the second "so" for emphasis. For example:

"The fudge was so rich and so creamy that it melted in my mouth."

Is the second "so" necessary? No. But it adds emphasis and makes it clear that we want to apply a "so" to both of the modifiers.

I hope that helps!