Last visit was: 08 Jul 2025, 10:30 It is currently 08 Jul 2025, 10:30
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
555-605 Level|   Parallelism|                  
User avatar
AryamaDuttaSaikia
User avatar
Jamboree GMAT Instructor
Joined: 15 Jul 2015
Last visit: 06 Dec 2019
Posts: 252
Own Kudos:
687
 [3]
Given Kudos: 1
Status:GMAT Expert
Affiliations: Jamboree Education Pvt Ltd
Location: India
Posts: 252
Kudos: 687
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
User avatar
maiebh
Joined: 22 Mar 2012
Last visit: 23 Mar 2017
Posts: 25
Own Kudos:
Given Kudos: 62
Location: Brazil
Concentration: Leadership, Strategy
GMAT 1: 610 Q42 V33
GMAT 2: 660 Q44 V36
GMAT 3: 710 Q46 V41
WE:General Management (Education)
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
sayantanc2k
Joined: 14 Dec 2013
Last visit: 09 Dec 2022
Posts: 2,395
Own Kudos:
15,461
 [3]
Given Kudos: 26
Location: Germany
Schools:
GMAT 1: 780 Q50 V47
WE:Corporate Finance (Pharmaceuticals and Biotech)
Expert
Expert reply
Schools:
GMAT 1: 780 Q50 V47
Posts: 2,395
Kudos: 15,461
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
avatar
stevekeating
Joined: 03 Sep 2015
Last visit: 30 Jun 2025
Posts: 48
Own Kudos:
Expert
Expert reply
Posts: 48
Kudos: 223
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Dear R26, I guess you mean the comma after the word “job”. When I look at the sentence, it seems not to be underlined. However, I don’t think you need to worry about this comma. The equations have reduced three things. The second and third thing must be separated by “and”. Whether there is a comma there or not doesn’t matter. Eliminate A, B and D. As mentioned, “was lowered” in E is redundant. Choose C. Fortunately, the GMAT is not a test of punctuation!
User avatar
AryamaDuttaSaikia
User avatar
Jamboree GMAT Instructor
Joined: 15 Jul 2015
Last visit: 06 Dec 2019
Posts: 252
Own Kudos:
Given Kudos: 1
Status:GMAT Expert
Affiliations: Jamboree Education Pvt Ltd
Location: India
Posts: 252
Kudos: 687
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The sentence is in two parallel parts. The first part says "shift-work equations" has 1."reduced sickness", 2. "sleeping on the job",and 3."fatigue.". The second part of the sentence is the result of 1,2, and 3 which is raising production efficiency. Hence raising is the result of these three actions. Hence it should be in " ing " form. The answer therefore cannot be "B" and is "C."
User avatar
iliavko
Joined: 08 Dec 2015
Last visit: 28 Apr 2019
Posts: 256
Own Kudos:
Given Kudos: 36
GMAT 1: 600 Q44 V27
Products:
GMAT 1: 600 Q44 V27
Posts: 256
Kudos: 132
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I know it changes the meaning, but would a sentence like this be correct?

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and production efficiency in various industries.

Honestly I can't understand the rule used to arrive to choice C... There seem to be 10 different opinions and I couldn't see a solid rule that could be applied in all cases (99% of cases)

Can we have a list with, say 10 elements? "I like 1,2,3,4,5,6,7,8,9, and 10" ? There is no limit to the number of elements in a list, since they are all parallel, right?

Another one, somebody used this way to see it and this one does make sense to be a solid rule:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, have reduced sleeping on the job, have reduced fatigue among shift workers, and have reduced have raised production efficiency in various industries. -> Wrong, doesn't make sense, need to change.

Is this way to analyse it correct?

Thank you!
User avatar
EducationAisle
Joined: 27 Mar 2010
Last visit: 08 Jul 2025
Posts: 3,874
Own Kudos:
Given Kudos: 159
Location: India
Schools: ISB
GPA: 3.31
Expert
Expert reply
Schools: ISB
Posts: 3,874
Kudos: 3,572
Kudos
Add Kudos
Bookmarks
Bookmark this Post
iliavko
I know it changes the meaning, but would a sentence like this be correct?

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and production efficiency in various industries.
To say that this sentence changes the meaning, would be too mild. This sentence is actually not making any sense. This is suggesting that recently implemented "shift-work equations" have reduced four things:

i) sickness
ii) sleeping on the job,
iii) fatigue among shift workers and
iv) production efficiency

The reason this does not make sense, is because if sickness, sleeping, and fatigue are reduced, there is no reason why production efficiency should also reduce.

Quote:
Another one, somebody used this way to see it and this one does make sense to be a solid rule:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, have reduced sleeping on the job, have reduced fatigue among shift workers, and have reduced have raised production efficiency in various industries. -> Wrong, doesn't make sense, need to change.

Is this way to analyse it correct?
Absolutely. In fact, our book EducationAisle Sentence Correction Nirvana discusses the parallelism philosophy through a simplified XYZ deconstruct, its application and examples in significant detail. If someone is interested, PM me your email-id, I can mail the corresponding section.
User avatar
iliavko
Joined: 08 Dec 2015
Last visit: 28 Apr 2019
Posts: 256
Own Kudos:
Given Kudos: 36
GMAT 1: 600 Q44 V27
Products:
GMAT 1: 600 Q44 V27
Posts: 256
Kudos: 132
Kudos
Add Kudos
Bookmarks
Bookmark this Post
yes, yes I understand it makes no sense, but for example purposes, imagine that it does make sense for some reason, then the list would be correct? Is there a limit to the number of elements you can list? No, right?..
But it seems that on Gmat they like to use "1,2 and 3"-lists, so 3elements in parallel and then something else happens.

Let's make the example sentence more logical:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and labor accidents in various industries. -> would this be correct? Here I don't like the (comma)-And formation, wouldn't it require an Independent clause? I'm a bit confused with this...

And good to know that the XYZ analysis works. Its good to have a checker-rule!

Thank you.
User avatar
EducationAisle
Joined: 27 Mar 2010
Last visit: 08 Jul 2025
Posts: 3,874
Own Kudos:
3,572
 [1]
Given Kudos: 159
Location: India
Schools: ISB
GPA: 3.31
Expert
Expert reply
Schools: ISB
Posts: 3,874
Kudos: 3,572
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
iliavko
yes, yes I understand it makes no sense, but for example purposes, imagine that it does make sense for some reason, then the list would be correct? Is there a limit to the number of elements you can list? No, right?..
Correct.

Quote:
Let's make the example sentence more logical:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and labor accidents in various industries. -> would this be correct?
Yes.

Quote:
Here I don't like the (comma)-And formation, wouldn't it require an Independent clause? I'm a bit confused with this...
It's just a list (more than 2 elements), and hence, there is a comma. Another officially correct sentence:

Twenty-two feet long and 10 feet in diameter, the AM-1 is one of the many new satellites that are part of a 15-year effort to subject the interactions of Earth's atmosphere, ocean, and land surfaces to detailed scrutiny from space.

Notice the comma before and land surfaces.

Having said that, the presence or absence of comma before and should not be a reason for you to select/ignore an option.
User avatar
amarinetti
Joined: 05 Apr 2016
Last visit: 05 Jan 2017
Posts: 18
Own Kudos:
Given Kudos: 23
Posts: 18
Kudos: 11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
One question. Raising is not parallel with have reduced. I think the correct answer would have been: and fatigue among shift workers while they have raised...

Am I right???
User avatar
sayantanc2k
Joined: 14 Dec 2013
Last visit: 09 Dec 2022
Posts: 2,395
Own Kudos:
15,461
 [1]
Given Kudos: 26
Location: Germany
Schools:
GMAT 1: 780 Q50 V47
WE:Corporate Finance (Pharmaceuticals and Biotech)
Expert
Expert reply
Schools:
GMAT 1: 780 Q50 V47
Posts: 2,395
Kudos: 15,461
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Mariwa
One question. Raising is not parallel with have reduced. I think the correct answer would have been: and fatigue among shift workers while they have raised...

Am I right???

Consider "while" not as a parallelism marker, but as a contrast marker.

Consider the sentence this way:

Independent clause, present participle modifier (modifying the entire clause preceding it):
Equations have reduced fatigue, (while) raising the efficiency.

Since the modification is to show a contrast, "while" is added before the present participle.

Since this is an official question, it can be inferred that GMAC accepts such use of "while", though I do agree that the sentence you have mentioned is better.
avatar
Prateek176
Joined: 12 Mar 2017
Last visit: 10 Jun 2021
Posts: 181
Own Kudos:
Given Kudos: 87
Location: India
Concentration: Strategy, General Management
GMAT 1: 700 Q49 V37
GPA: 4
GMAT 1: 700 Q49 V37
Posts: 181
Kudos: 89
Kudos
Add Kudos
Bookmarks
Bookmark this Post
skim
The Official Guide for GMAT Review, 10th Edition, 2003

Practice Question
Question No.: SC 233
Page: 690
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and have raised production efficiency in various industries.

(A) fatigue among shift workers, and have raised

(B) fatigue among shift workers, and raised

(C) and fatigue among shift workers while raising

(D) lowered fatigue among shift workers, and raised

(E) and fatigue among shift workers was lowered while raising


The best answer, C, grammatically states that the equations... have reduced x, y, and i. and have raised efficiency. Choices A and B fail to use and to signal that fatigue among shift workers completes the series begun by have reduced, and so produce awkward and unclear sentences. Both D and E fail to use and to introduce the last item in the list, which is sleeping in these constructions. In E, while raising has no logical referent, producing only the absurd statement that fatigue has raised efficiency.


This is question #134 of the 12th ed OG. I don't understand why in option (D), the OE states: "lowered before fatigue illogically suggests that fatigue actually increased"

On a separate note, what is the difference between "among" and "amongst" in GMAT context? Is there any particular rule pertaining to these two words?

GMATNinja , egmat , VeritasKarishma , MartyMurray

I am finding it difficult to accept C as the answer choice. As per my understanding, "while" is a subordinator and required a bonafide verb which is clearly missing here in option C. Can anybody please help me understand?
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,476
Own Kudos:
5,486
 [4]
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,476
Kudos: 5,486
 [4]
1
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
Prateek176
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and have raised production efficiency in various industries.

(C) and fatigue among shift workers while raising

I am finding it difficult to accept C as the answer choice. As per my understanding, "while" is a subordinator and required a bonafide verb which is clearly missing here in option C. Can anybody please help me understand?

"While" can be used in two ways.

It can be used to start a clause. In such cases "while" is similar to "whereas," and the clause so begun is a subordinate clause.

"While" can also be used to convey, simply, "at the same time", without the connotations of the word "whereas." When used in this way, "while" can be used to begin a clause, but what follows "while" that means "at the same time" does not have to be a clause.

Consider the following examples:

"While" Begins Clause: While the guests were enjoying the sunset, the band set up.

The above sentence conveys that the band set up as the guests were enjoying the sunset.

"While" Without Clause: While setting up, the band members discussed the song list.

This above sentence conveys that, as they were setting up, the band members discussed the song list.

"While Without Clause: My uncle Harry would sing opera while skiing in the Alps.

Notice, in this last sentence, there is no comma before "while". When "while" means "when", you don't need a comma before it. When "while" means "whereas" and begins a clause, the clause has to be separated from the rest of the sentence by a comma.

Here's another example without a comma:

We ran around town while our parents were shopping for bicycles.

The fact that "while" is not preceded by a comma confirms that, in this case, it does not mean "whereas".
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 08 Jul 2025
Posts: 16,101
Own Kudos:
74,207
 [2]
Given Kudos: 475
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,101
Kudos: 74,207
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Prateek176
skim
The Official Guide for GMAT Review, 10th Edition, 2003

Practice Question
Question No.: SC 233
Page: 690
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and have raised production efficiency in various industries.

(A) fatigue among shift workers, and have raised

(B) fatigue among shift workers, and raised

(C) and fatigue among shift workers while raising

(D) lowered fatigue among shift workers, and raised

(E) and fatigue among shift workers was lowered while raising


The best answer, C, grammatically states that the equations... have reduced x, y, and i. and have raised efficiency. Choices A and B fail to use and to signal that fatigue among shift workers completes the series begun by have reduced, and so produce awkward and unclear sentences. Both D and E fail to use and to introduce the last item in the list, which is sleeping in these constructions. In E, while raising has no logical referent, producing only the absurd statement that fatigue has raised efficiency.


This is question #134 of the 12th ed OG. I don't understand why in option (D), the OE states: "lowered before fatigue illogically suggests that fatigue actually increased"

On a separate note, what is the difference between "among" and "amongst" in GMAT context? Is there any particular rule pertaining to these two words?

GMATNinja , egmat , VeritasKarishma , MartyMurray

I am finding it difficult to accept C as the answer choice. As per my understanding, "while" is a subordinator and required a bonafide verb which is clearly missing here in option C. Can anybody please help me understand?

An adverb clause can be reduced to an adverbial phrase if it has the same subject as the main clause.

While I was skiing, I saw ...
is same as
While skiing, I saw ...

It reflects that the two happened "at the same time".


Recently implemented "shift-work equations" ... have reduced A, B, and C while raising production efficiency ...

is same as

Recently implemented "shift-work equations" ... have reduced A, B, and C while they are raising production efficiency ...
User avatar
Harsh2111s
Joined: 08 May 2019
Last visit: 10 Feb 2021
Posts: 317
Own Kudos:
Given Kudos: 54
Location: India
Concentration: Operations, Marketing
GPA: 4
WE:Manufacturing and Production (Manufacturing)
Products:
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Quote:
skim
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping on the job, fatigue among shift workers, and have raised production efficiency in various industries.

(A) fatigue among shift workers, and have raised

(B) fatigue among shift workers, and raised

(C) and fatigue among shift workers while raising

(D) lowered fatigue among shift workers, and raised

(E) and fatigue among shift workers was lowered while raising

AjiteshArun GMATNinja,

I have a questions here.
Need support to eliminate option A. I am not satisfied with mentioned answers.
User avatar
AjiteshArun
User avatar
Major Poster
Joined: 15 Jul 2015
Last visit: 01 Jun 2025
Posts: 5,949
Own Kudos:
Given Kudos: 732
Location: India
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Expert
Expert reply
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Posts: 5,949
Kudos: 5,054
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Harsh2111s
AjiteshArun GMATNinja,

I have a questions here.
Need support to eliminate option A. I am not satisfied with mentioned answers.
Hi Harsh2111s,

Let's take a look at the list:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced
(a) sickness,
(b) sleeping on the job,
(c) fatigue among shift workers,
and
(d) have raised production efficiency

The first three are nouns, and make sense with have reduced (have reduced sickness, have reduced sleeping, have reduced fatigue), but after that, we run into a verb phrase (have raised...) instead of a noun, and we end up with have reduced have raised production efficiency as the final element in the list.
User avatar
Harsh2111s
Joined: 08 May 2019
Last visit: 10 Feb 2021
Posts: 317
Own Kudos:
Given Kudos: 54
Location: India
Concentration: Operations, Marketing
GPA: 4
WE:Manufacturing and Production (Manufacturing)
Products:
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Quote:
Let's take a look at the list:

Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced
(a) sickness,
(b) sleeping on the job,
(c) fatigue among shift workers,
and
(d) have raised production efficiency

The first three are nouns, and make sense with have reduced (have reduced sickness, have reduced sleeping, have reduced fatigue), but after that, we run into a verb phrase (have raised...) instead of a noun, and we end up with have reduced have raised production efficiency as the final element in the list.
[/quote]

But I think have is used to make things parallel.
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping......,fatigue.....(have reduced sickness, have reduced sleeping, have reduced fatigue))and

Recently implemented "shift-work equations" based on studies of the human sleep cycle have raised production efficiency.

Need some more input.
User avatar
AjiteshArun
User avatar
Major Poster
Joined: 15 Jul 2015
Last visit: 01 Jun 2025
Posts: 5,949
Own Kudos:
Given Kudos: 732
Location: India
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Expert
Expert reply
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Posts: 5,949
Kudos: 5,054
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Harsh2111s
But I think have is used to make things parallel.
Recently implemented "shift-work equations" based on studies of the human sleep cycle have reduced sickness, sleeping......,fatigue.....(have reduced sickness, have reduced sleeping, have reduced fatigue))and

Recently implemented "shift-work equations" based on studies of the human sleep cycle have raised production efficiency.

Need some more input.
Hi Harsh2111s,

That's one way of looking at it, but then we'd really need two lists, which would in turn mean that we'd expect to see two conjunctions in the sentence.

Equations have reduced (X, Y, and Z), and have raised (B).

To see why it'd be much better to include the second conjunction, check if you'd be comfortable with the following sentence:

Equations have reduced X, Y, and have raised B.
avatar
NimishaKrishna
Joined: 26 Jan 2020
Last visit: 15 Jan 2021
Posts: 9
Own Kudos:
Given Kudos: 11
Posts: 9
Kudos: 11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Will it be correct if the sentence structure in A is as below

'have reduced X,Y and Z and have raised'

Can someone please clarify?
User avatar
AjiteshArun
User avatar
Major Poster
Joined: 15 Jul 2015
Last visit: 01 Jun 2025
Posts: 5,949
Own Kudos:
Given Kudos: 732
Location: India
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Expert
Expert reply
GMAT Focus 1: 715 Q83 V90 DI83
GMAT 1: 780 Q50 V51
GRE 1: Q170 V169
Posts: 5,949
Kudos: 5,054
Kudos
Add Kudos
Bookmarks
Bookmark this Post
NimishaKrishna
Will it be correct if the sentence structure in A is as below

'have reduced X,Y and Z and have raised'

Can someone please clarify?
Hi NimishaKrishna,

Doing that would certainly remove that particular error, but it is hard to say whether option A would then be "correct". Generally, we should avoid evaluating altered options, because we'd then be going by our own opinions, instead of those of the GMAT.
   1   2   3   
Moderators:
GMAT Club Verbal Expert
7349 posts
GMAT Club Verbal Expert
235 posts