By pressing a tiny amount of nitrogen between two diamonds to a pressu

Dear Friends,

Here is a detailed explanation to this question-

Concepts tested here: Idioms

• “not only A but also B” is the correct, idiomatic usage; A must be parallel to B.
• “not only A but B” is a correct idiom; A must be parallel to B.

A: This answer choice fails to maintain parallelism between A (“were able to transform the gas into a solid”) and B (“they also created a semiconductor similar to silicon”) in the idiomatic construction “not only A but B”; please remember, “not only A but B” is a correct idiom; A must be parallel to B.

B: This answer choice fails to maintain parallelism between A (“were able to transform the gas into a solid”) and B (“creating a semiconductor similar to silicon”) in the idiomatic construction “not only A but B”; please remember, “not only A but B” is a correct idiom; A must be parallel to B.

C: Correct. This answer choice correctly maintains parallelism between A (“to transform the gas into a solid”) and B (“to create a semiconductor similar to silicon”) in the idiomatic construction “not only A but B”.

D: This answer choice fails to maintain parallelism between A (“to transform the gas into a solid”) and B (“creating a semiconductor similar to silicon”) in the idiomatic construction “not only A but B”; please remember, “not only A but B” is a correct idiom; A must be parallel to B.

E: This answer choice fails to maintain parallelism between A (“able to transform the gas into a solid”) and B (“they were also able to create a semiconductor similar to silicon”) in the idiomatic construction “not only A but B”; please remember, “not only A but B” is a correct idiom; A must be parallel to B.

Hence, C is the best answer choice.

Additional Note: Please keep in mind that “not only A but B” is considered inferior to the construction “not only A but also B”, but it is not incorrect and can be used in a correct answer choice.

All the best!
Experts' Global Team

OK, let me try to explain a bit more elaborately. Consider this way:

Parallelism marker: NOT ONLY (X), BUT ALSO (Y).
X and Y should be parrallel.

Correct: Scientists were NOT ONLY ( able to transform), BUT ALSO ( able to create).
able to transform and able to create are parallel.

Correct: NOT ONLY (Scientists were able to transform), BUT ALSO ( they were able to create).
Scientists were able to transform and they were able to create are parallel.

Wrong: Scientists were NOT ONLY ( able to transform), BUT ALSO ( they were able to create).
able to transform and they were able to create are NOT parallel.

I stumbled upon a great explanation by "Ron". Sharing it for benefit of others

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There is really only one base structure here, which is "not ... but ..."

that's actually the only TRUE set of parallel markers here. "only" and "also" are adverbs, and so ultimately function as modifiers -- i.e., they aren't necessary to the structure.
Still, since "not only ... but also ..." is so common, you may want to memorize it separately -- but be aware that this is NOT the only correct form of this idiom.

The MOST reliable way to deconstruct this idiom is just to memorize "not ... but ...", and then ignore the adjectives "only" and "also" in deciding whether structures are grammatically parallel.
In deciding the MEANING of the structure, you can't dismiss "only" and "also" ... but that's a separate issue.

EXAMPLES: BE SURE YOU CAN UNDERSTAND WHY EACH OF THESE IS CORRECT OR INCORRECT

the writer was not only mortified by her mistake but determined to correct it in print.
--> CORRECT

the writer not only was mortified by her mistake but was determined to correct it in print.
--> CORRECT

the writer was not only mortified by her mistake but was determined to correct it in print.
--> INCORRECT

the small child was relieved to hear that the rustling under the bed was caused not by a ghost but by his pet cat.
--> CORRECT

the small child was relieved to hear that the rustling under the bed was caused not by a ghost but his pet cat.
--> INCORRECT

SO WHAT'S THE DIFFERENCE, THEN, WITH
"not only ... but also ..."
"not only ... but ..."
"not ... but ..."
?

The difference here is strictly one of MEANING.

The first two are pretty similar; the last one is TOTALLY different.

(1) "not only ... but also ..." is used to refer to two descriptions that REINFORCE each other (i.e., both have the same connotation -- two good things, two bad things, two helpful things, etc.), but are fundamentally independent.
ex:
this drug is not only an alertness aid, but also an antidepressant.
--> "alertness aid" and "antidepressant" are TWO GOOD THINGS that have basically NOTHING TO DO WITH EACH OTHER.
Therefore, "not only ... but also".

Wrong: The drug not only kills the bacteria but also kills white cells. (Doesn’t make sense as explained, one good, one bad -- so the context here is inappropriate)
[Correct Version can be written with just “but”: The drug kills the bacteria but also kills white cells.]

Correct: The drugs not only kills the bacteria but also alleviates joint pain. (Both effects described are positive)

(2) "not only ... but ..." is also used to refer to two descriptions that REINFORCE each other, but it's generally used when the second description EXPANDS or GOES BEYOND the first.
ex:
ryan not only competed in all the events, but won first prize in three of them.
--> Note that "won first prize in three of [the events]" is an EXTENSION of "compete[ing] in all the events". These are not independent.

The above difference between (1) and (2) is subtle, and is therefore not terribly important. However, you MUST be able to tell those from the next one:

(3) "not ... but ..." is used when the FIRST thing is EXPECTED, ASSUMED, or PREVIOUSLY THOUGHT, but is REFUTED / CONTRADICTED / DISPROVED by the SECOND thing.
ex:
the snacks known as "French fries" were invented not in France, but in Belgium.
--> The initial assumption, which is refuted, is that French fries are from France.

--> I was surprised to learn that Ella was not Clint's biological daughter but in fact his adopted daughter, since her facial features so closely resemble his.
(Here, since the girl looks so much like her dad, we EXPECT to find out that she's his biological daughter.)

[Other scenarios:

"not only....also..."

 This could work, if there were some other transition signal (e.g. a semicolon) to replace the missing "but".
For instance:
The Acme Battery Corporation does not only make batteries; it also makes battery accessories, such as chargers.

In this case, the meaning is largely the same as that of "not only ... but also..."

"not only ... also" doesn't make grammatical sense; the inclusion of the conjunction "but" is of the utmost importance. If you don't have this conjunction, then the sentence thus created becomes a run-on

"not....but also..."
 Doesn't seem logical under any circumstances

"X but Y":
this just implies a contrast, but NOT any expectation.
e.g.,
I am not a mechanic, but can perform basic maintenance on non-hybrid cars.
]

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Hope it can explain why C is correct

"Scientists were" is OUTSIDE the parallelism structure and hence covers both NOT ONLY.... and BUT ALSO.....

Thus using "they were" within the second element (BUT ALSO) is wrong. If "they were" is to be used within the second element (BUT ALSO), then "scientists were" should also be brought WITHIN the first element (NOT ONLY). Then the sentence would be:

..not only scientists were able to transform the gas into a solid, but they were also able to
create....

According to my understanding, the following construcions are...

NOT ONLY X BUT ALSO Y: CORRECT
NOT ONLY X BUT IT/THEY ALSO Y: INCORRECT
NOT ONLY X BUT Y: CORRECT
X, BUT Y: CORRECT
X, BUT ALSO Y: CORRECT

There is a way to check in not only X but also Y or not only X but Y construction whether selected choice is correct.

<Modifier>....., scientists not only were able to transform the gas into a solid, but they also created a semiconductor similar to
silicon.

So, scientists were able to do two things which should stand independently by themselves.

A. not only were able to transform the gas into a solid, but they also created
B. not only were able to transform the gas into a solid but also creating
C. were able not only to transform the gas into a solid but to create
D. were able not only to transform the gas into a solid but also creating
E. were not only able to transform the gas into a solid, but they were also able to create

Choice C:
Scientists were able not only to transform the gas into a solid.
Scientists were able but to create a semiconductor similar to silicon.

Both are independent sentences that can stand by their own.This method has helped me quickly eliminate choices in this type of construction.Like in this sentence, choices B & D can be eliminated easily. Hope it helps you too!

Thanks for your reply.

I have also seen NOT ONLY....BUT THEY ALSO.... in some other correct question.
What do you think about that?

I would have chosen "D" first, but i noticed that "creating" is not parallel to "transform", so that only "C" is correct. Even though it is "not only X" .. "but Y" without also. Thanks for the questions and explanation

By pressing a tiny amount of nitrogen between two diamonds to a pressure of 25 million pounds per square inch, scientists not only were able to transform the gas into a solid, but they also created a semiconductor similar to silicon.

(A) not only were able to transform the gas into a solid, but they also created -- Not only X , but also Y -- parallelism issue -- they in part after that
(B) not only were able to transform the gas into a solid but also creating -- parallelism issue
(C) were able not only to transform the gas into a solid but to create - Correct
(D) were able not only to transform the gas into a solid but also creating -- parallelism issue
(E) were not only able to transform the gas into a solid, but they were also able to create -- parallelism issue -- they in the part after but
Answer C

'not only ... but also' in generally preferred, but gmatprep has featured at least one problem featuring 'not only ... but' in the correct answer

the correct answer is c, the only choice that features proper parallelism. it omits the word 'also', but it's still correct.

not only X...but Y is ALSO an idiom

A. not only were able to transform the gas into a solid, but they also created not parallel
B. not only were able to transform the gas into a solid but also creating not parallel
C. were able not only to transform the gas into a solid but to create parallel!
D. were able not only to transform the gas into a solid but also creating not parallel
E. were not only able to transform the gas into a solid, but they were also able to not parallel
create

In what way is parallelism missing in E?

The option says "the scientists were not only able to transform..., but also able to create..." which seems parallel to me (or am I missing something?)


Thanks in advance!

Hello himanshu0123,

We hope this finds you well.

To answer your query, the inclusion of "they" forms an independent clause on one side of the parallelism marker, thus breaking parallelism with the verb phrase "were able to transform".

We hope this helps.
All the best!
Experts' Global Team

Not only x but also y is a correlative conjunction. A correlative conjunction joins two equal elements. In the sentence above, the elements, to transform the gas and created a semiconductor, are not equal hence the reason "not only but also" is not correct.

According to whatever little bit knowledge I have, I don't think NOT ONLY... BUT THEY ALSO can be correct. What I have read is correct idiom should be NOT ONLY X .... BUT ALSO Y, where X and Y should be parallel. Can you provide some examples or source?

Thanks.

Hey noboru,

In my opinion its not correct; May be the sentence you encountered is using "NOT ONLY....BUT THEY ALSO" in some context.

But its not the correct idiom.

Thanks

Here is an example:

Not only did the systematic clearing of forests in the United States
create farmland (especially in the Northeast) and gave consumers relatively
inexpensive houses and furniture, but it also caused erosion and very
quickly deforested whole regions.
A. Not only did the systematic clearing of forests in the United States create
farmland (especially in the Northeast) and gave consumers relatively
inexpensive houses and furniture, but it also
B. Not only did the systematic clearing of forests in the United States create
farmland (especially in the Northeast), which gave consumers relatively
inexpensive houses and furniture, but also
C. The systematic clearing of forests in the United States, creating farmland
(especially in the Northeast) and giving consumers relatively inexpensive
houses and furniture, but also
D. The systematic clearing of forests in the United States created farmland
(especially in the Northeast) and gave consumers relatively inexpensive houses
and furniture, but it also
E. The systematic clearing of forests in the United States not only created
farmland (especially in the Northeast), giving consumers relatively inexpensive
houses and furniture, but it

What is your take?