Ozone

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src_saurav: Master | Next Rank: 500 Posts; Posts: 145; Joined: Sun Mar 15, 2015 7:27 amFollowed by: 1 member; Thanked: 2 times

by src_saurav » Mon May 11, 2015 5:47 am

88. Often visible as smog, ozone is formed in the
atmosphere from hydrocarbons and nitrogen oxides,
two major pollutants emitted by automobiles, react
with sunlight.
(A) ozone is formed in the atmosphere from
(B) ozone is formed in the atmosphere when
(C) ozone is formed in the atmosphere, and when
(D) ozone, formed in the atmosphere when
(E) ozone, formed in the atmosphere from

D is my answer ...B is OA.Please explain ur technique.

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Source: Beat The GMAT — Sentence Correction | Mon May 11, 2015 5:47 am

binit: Master | Next Rank: 500 Posts; Posts: 111; Joined: Sat Mar 07, 2015 11:00 pmFollowed by: 1 member; Thanked: 8 times

by binit » Tue May 12, 2015 2:04 pm

88. Often visible as smog, ozone is formed in the
atmosphere from hydrocarbons and nitrogen oxides,
two major pollutants emitted by automobiles, react
with sunlight.
(A) ozone is formed in the atmosphere from
(B) ozone is formed in the atmosphere when
(C) ozone is formed in the atmosphere, and when
(D) ozone, formed in the atmosphere when
(E) ozone, formed in the atmosphere from

Hey, pls don't forget to underline the part being questioned. That makes it a lot easier for guys (like me

)to solve a problem under time.
My technique:
The last part - react with sunlight - indicates some plural subject, ozone wont do; so, that must be hydrocarbons and nitrogen oxides.
in A. react with sunlight has no clear subject.
in B. react with sunlight clearly has hydrocarbons and nitrogen oxides. as subject. Bingo!
C. is a sentence fragment. (after 'and' we should have a subject and an agreed verb not just a when clause)
D. is also a sentence fragment. (ozone has only MODIFIERS to follow)
E. implies ozone react with sunlight. S-V agreement error.
Hope these make sense

~Binit.

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ceilidh.erickson: GMAT Instructor; Posts: 2095; Joined: Tue Dec 04, 2012 3:22 pmFollowed by: 247 members; Thanked: 1443 times

by ceilidh.erickson » Wed May 13, 2015 10:35 am

Binit's explanation was perfectly on point.

As a more general rule, we can look at the differences between the answer choices to tell us what is being tested.

A, B, and C begin with "ozone is formed," while D and E have "ozone, formed..." If some answer choices express the idea of "formed" as a verb and some express it as a modifier, we then ask ourselves - should that be a verb? Or does the subject "ozone" have another verb elsewhere? As Binit pointed out, the only other verb is "react," which cannot go with the singular "ozone." We can rule out D and E.

We could then look to the difference between "from" and "when." "From" would be introducing a prepositional phrase, while "when" would be introducing a subordinate clause. Because we have the verb "react" in the non-underlined portion, it must be a clause, not a prepositional phrase. Eliminate A.

Now, the final difference between B and C is "and." When we have a conjunction (e.g. "and") after an independent clause (in this case "ozone is formed"), there must also be an independent clause after it. The "when" makes the second clause subordinate, though, so C is a fragment.

The answer must be B.

Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education

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akash singhal: Master | Next Rank: 500 Posts; Posts: 152; Joined: Fri Apr 24, 2015 1:39 amFollowed by: 3 members; Location: Rourkela Odisha India; Thanked: 2 times; GMAT Score:650

by akash singhal » Wed May 13, 2015 11:24 pm

ceilidh.erickson wrote:Binit's explanation was perfectly on point.

As a more general rule, we can look at the differences between the answer choices to tell us what is being tested.

A, B, and C begin with "ozone is formed," while D and E have "ozone, formed..." If some answer choices express the idea of "formed" as a verb and some express it as a modifier, we then ask ourselves - should that be a verb? Or does the subject "ozone" have another verb elsewhere? As Binit pointed out, the only other verb is "react," which cannot go with the singular "ozone." We can rule out D and E.

We could then look to the difference between "from" and "when." "From" would be introducing a prepositional phrase, while "when" would be introducing a subordinate clause. Because we have the verb "react" in the non-underlined portion, it must be a clause, not a prepositional phrase. Eliminate A.

Now, the final difference between B and C is "and." When we have a conjunction (e.g. "and") after an independent clause (in this case "ozone is formed"), there must also be an independent clause after it. The "when" makes the second clause subordinate, though, so C is a fragment.

The answer must be B.

Thanks for your explanation...
I just have one doubt what determines that the sentence is a fragment ... and what is the purpose of using fragments?????

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