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

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

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.

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.

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.

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

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.

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

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

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

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

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