Imperceptible to the eye or the ear, carbon monoxide is formed from ma

Question

Imperceptible to the eye or the ear,  carbon monoxide is formed from  materials containing carbon, or carbonaceous materials, are only partially combusted.

(A) carbon monoxide is formed from

(B) carbon monoxide is formed by

(C) the formation of carbon monoxide is when

(D) carbon monoxide is formed when

(E) carbon monoxide forms when its

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Bunuel · Accepted Answer

KAPLAN OFFICIAL EXPLANATION:

As we saw in number 17, this sentence begins with a modifier. Unlike the modifier in that sentence, this one is used correctly because it does indeed modify carbon monoxide. Eliminate (C) for creating an error where there was none. Next, you need to decide whether from, by, or when should end the underlined section. When you originally read the sentence, you probably noticed that something was very wrong. Since you can't change the end of the sentence, you need to alter the underlined portion in order to make the sentence grammatically correct. Only when does that (try reading them in), so eliminate (A) and (B). Finally, (D) is better than (E) because in this case the passive is formed is more accurate than forms and because the its in (E) is unnecessary.  Go with (D).

Sumi1010 · Answer

The sentence is : 
 Imperceptible to the eye or the ear,  carbon monoxide is formed from materials  containing carbon, or carbonaceous materials,   are  only partially combusted.

Dropping the modifiers - 
carbon monoxide is formed from materials  are  only partially combusted.
Carbon monoxide is singular. Thus, ARE can't be used for it. 
If "only partially combustible" modifies  materials  , ARE is not needed.

Choices - 
(A) carbon monoxide is formed from
 If "only partially combustible" modifies  materials  , ARE is not needed.  
(B) carbon monoxide is formed by
 If "only partially combustible" modifies  materials  , ARE is not needed.  
(C) the formation of carbon monoxide is when
 "Imperceptible to the eye or the ear" wrongly modifies the formation.  
(D) carbon monoxide is formed when
 Correct. "only partially combustible" modifies  materials   
(E)  carbon monoxide forms  when its
 Carbon monoxide does not do anything to form itself. Something else forms it.

D

hk111 · Answer

Core of the sentence :  carbon monoxide is formed from  materials containing carbon are only partially combusted

(A) carbon monoxide is formed from
 - Incorrect phrasing.  Eliminate  
 A "when" would be needed here

(B) carbon monoxide is formed by
- Same as (A).  Eliminate

(C) the formation of carbon monoxide is when
- Passive voice and incorrect phrasing.  Eliminate

(D) carbon monoxide is formed when
- correct use of "when" and contains a valid working verb.   Keep

(E) carbon monoxide forms when its
- No working verb present and this incorrect phrasing.  Eliminate

IMO D

zhanbo · Answer

My answer is  (D) . It took me 01:47.

(A) This version is not constructed appropriately as a sentence. 
The main clause seems to be "carbon monoxide is formed from materials containing carbon, or carbonaceous materials", so we are surprised to encounter "are only partially combusted" as its subject is missing.

(B) See above.

(C) The subject should be compatible with the modifier "Imperceptible to the eye or the ear". "the formation of carbon monoxide" is incorrect.

(E) The issue is with "its". CO2 does not own carbonaceous materials. Rather, CO2 is formed by partial combustion of carbonaceous materials.

Any difference between "carbon monoxide is formed" and "carbon monoxide forms". I personally feel either is okay but would like to confirm with OA.

asishron29181 · Answer

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

(D) carbon monoxide is formed when  - Conveys the correct meaning. Modifier usage is taken care of at the same time.

TarunKumar1234 · Answer

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

(A) carbon monoxide is formed from -> "from" makes "materials containing carbon, or carbonaceous materials" a prepositional phrase. Here, sentence construction is the issue. We can't say, carbon monoxide is formed..... are only partially combusted.

(B) carbon monoxide is formed by-> Same as A.

(C) the formation of carbon monoxide is when -> Now, when makes sentence better. But, we need "carbon monoxide" as modifier. Incorrect.

(D) carbon monoxide is formed when -> Now, due to introduction of "when", sentence becomes as "materials...., are only partially combusted". It makes sense. Let's keep it.

(E) carbon monoxide forms when its -> Incorrect Pronoun "its"

So, I think D.

carouselambra · Answer

IMO D

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

Skeleton of the sentence :
Imperceptible to the eye or the ear, <needs a subject> is formed .....<are only partially combusted>

(A) carbon monoxide is formed from
Makes the sentence awkward as the presence of "are only partially combusted" needs a situation.

(B) carbon monoxide is formed by
Makes the sentence awkward as the presence of "are only partially combusted" needs a situation.

(C) ~~the formation~~ of carbon monoxide is when

(D) carbon monoxide is formed when
Correct

(E) carbon monoxide forms when its
Changes the meaning of the sentence

akadiyan · Answer

Ans   D

(A) carbon monoxide is formed from -  INCORRECT 
The usage of 'from' after formed does not work with are only partially combusted", we need "When" in place of from.

(B) carbon monoxide is formed by -  INCORRECT 
Same error as above. The usage of 'by' changes the meaning of the sentence.

(C) the formation of carbon monoxide is when -  INCORRECT 
"Imperceptible to eye or the ear" modifies the formation rather than carbon monaxide.

(D) carbon monoxide is formed when -  CORRECT

(E) carbon monoxide forms when its  INCORRECT 
'its' refers to the materials of carbon monaxide incorrectly.

ramlala · Answer

Second part of sentence  'materials containing carbon, or carbonaceous materials, are only partially combusted'  is an act and shall be preceded by  when  and not by  from  and  by .

IMO D

private07 · Answer

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

(A) carbon monoxide is formed from - Incorrect - formed from is incorrect. Deviates the meaning of the sentence.

(B) carbon monoxide is formed by - Incorrect - formed by is incorrect

(C) the formation of carbon monoxide is when - Incorrect - Awkward and wordy

(D) carbon monoxide is formed when - Correct

(E) carbon monoxide forms when its - Incorrect - its is unnecessary

My answer is D

winterschool · Answer

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

(A) carbon monoxide  is formed from   Incorrect

two verb in single sentence

(B) carbon monoxide  is formed by   Incorrect

same as A

(C)  the formation  of carbon monoxide is when  Incorrect

the formation modifies by previous clause that is illogical

(D)  carbon monoxide is formed when   Correct

(E) carbon monoxide forms when  its   Incorrect

its uses redundant

jhavyom · Answer

Imperceptible to the eye or the ear,  carbon monoxide is formed from  materials containing carbon, or carbonaceous materials, are only partially combusted.

(A) carbon monoxide is formed from
The non-underlined part 'are only partially combusted.' does not have a subject.

(B) carbon monoxide is formed by
Same as A

(C) the formation of carbon monoxide is when
Misplaced modifier. The sentence must start with 'carbon monoxide'

(D) carbon monoxide is formed when
Correct

(E) carbon monoxide forms when its
Use of possessive its is incorrect

Choice D is the answer

CrackverbalGMAT · Answer

Imperceptible to the eye or the ear, carbon monoxide is formed from materials containing carbon, or carbonaceous materials, are only partially combusted.

A. carbon monoxide is formed from

Imperceptible to the eye or the ear, is a modifier that modifies carbon monoxide. 
The non underlined part says 
materials containing carbon, or carbonaceous materials,  are only partially combusted. 
 Are only partially combusted  talks about carbonaceous materials,
If we remove the modifier the sentence would read
Carbon monoxide is formed  from  carbonaceous materials, are only partially combusted.
The first clause - Carbon monoxide is formed from carbonaceous materials- has a subject (Carbon monoxide) and a verb (is formed)
What is the subject of the verb (are only partially combusted) in the next part of the sentence? Carbon monoxide or carbonaceous materials
The sentence construction is wrong.  Eliminate

(B) carbon monoxide is formed  by 
Same as A.  Eliminate .

(C)  the   formation  of carbon monoxide is when
What is- Imperceptible to the eye or the ear? Formation of carbon monoxide or carbon monoxide? It is the latter and hence must be placed next to the modifier.  Eliminate

(D) carbon monoxide is formed when

Now, the sentence would read
Carbon monoxide is formed  when  carbonaceous materials, are only partially combusted.
By adding “when”
Carbon monoxide is formed when carbonaceous materials, are only partially combusted.
The subject of the verb- are only partially combusted in the second clause is carbonaceous materials
 Correct .

(E) carbon monoxide forms  when its

Carbon monoxide forms when its carbonaceous materials, are only partially combusted.

The passive voice- “is formed” is preferred in this sentence.  Eliminate

Vishnupriya
CrackVerbal Prep Team

Imperceptible to the eye or the ear, carbon monoxide is formed from ma

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GMAT Sentence Correction (SC - EA only) Questions

Imperceptible to the eye or the ear, carbon monoxide is formed from ma

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