GMAT Idioms: Correlative Conjunctions

UPDATE: You can find this blog and others about idioms in our new GMAT Idiom eBook!


Conjunctions are joining words: they help to link together two nouns, or two verbs, or two larger structures in a sentence.  Coordinating conjunctions (e.g. “and”, “but”, “or”) simply link two words or parts — they can even link two independent clauses.  Subordinate conjunctions (“because”, “that”, “who”, etc.) introduce a subordinate clause, a dependent clause.  One unique feature of English is a third category, the correlative conjunctions — each is a pair of words or a pair of short phrases, and although separated in the sentence they act together as an organizing unit.  How this work can be particularly confusing to folks learning English as a second language.


Correlative conjunctions

either A or B

neither A nor B

both A and B

not A but B

not only A but also B

not just A but also B

not so much A as B

between A and B

just as A, so B

for every A, B

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The first two are “all purpose” in the sense that they can join two individual words (two nouns, two verbs, two adjectives, etc.) or phrases or even independent clauses.  These are the most flexible in their use.  Remember that “neither …nor” counts as a single negative, so another negative with these would be a double negative.


Contrast and joining

The next five require some comments.

both A and B

not A but B

not only A but also B

not just A but also B

not so much A as B

These can contrast single nouns or single verbs, but it’s much more likely for the GMAT to use them to set in parallel two of a more sophisticated structure (verb phrase, infinitives, participial phrase, gerund, etc.)   None of these are used to link two independent clauses.

Both A and B simply affirms both elements equally, whereas not A but B negates the first and affirms the second.  The next two, not only A but also B and not just A but also B, also affirms both elements, but with the connotations that A is more expected or more taken for granted and B is more of a surprise or something additional.

1) Beethoven was not only a great composer but also an electrifying pianist, according to contemporary accounts.

The first, “great composer”, is expected — anyone who has heard of Beethoven knows he’s a composer.  The second may come as a surprise to folks who are not particularly familiar with his biography.  This why the “not only … but also” idiom is more appropriate here than the “both … and” would be.

Be careful not to conflate these idioms —- typical GMAT mistake patterns include “not … but also” and “not only  … but”.  Make sure you know exactly how to use these.

The final one is the most sophisticated of these five: not so much A as B.  It demonstrates a difference in degree: whatever is being asserted, A is true or relevant, but it is less true or less relevant, and B is more so by comparison.  This is used for nouns primarily for nouns, noun-like phrase (infinitives & gerunds), prepositional phrase or participial phrases.

2) The CEO wants to organize a new division around these six products, not so much to promote the sales of these six as to establish a foothold in a new market sector.

3) In composing the Bill of Rights, the Founding Fathers valued not so much defending the rights of criminals as protecting any innocent person from unjust punishment.

4) Ironically, Columbus is remembered not so much for his original goal, finding the sea route to Asia, as for his accidental discovery, North America.

5) After his dramatic home run in the 1988 World Series, Gibson rounded the bases not so much running as hobbling.

This form can also contrast two verbs, with a format: [subject] “do not so much” [verb #1] “as” [verb #2].

6) Flying squirrels do not so much fly as glide in a long leap from tree to tree.


Between A and B

The word “between” is a preposition in this construction, so A & B must be either nouns, or something that could take the place of noun, such as a gerund.  The word “between” appears most frequently on the GMAT in the constructions “difference between” and “distinction between.”

7) “The difference between the right word and the almost right word is the difference between lightning and a lightning bug.”  — Mark Twain

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Just as A, so B

This construction is used only to link two independent clauses.  It sets up a comparison, and it is discussed further in the idioms of comparison.


For every A, B

Here, the word “for” is a preposition, so A and B have to be nouns.  In fact, in this idiom, A & B have to be concrete nouns.   This idiom discusses a correspondence, expressing the ratio between the elements of A and the elements of B.  It is frequently used in economic and political contexts.  In fact, this is a frequent idiom in GMAT math problems.

8) For every dollar Roscoe Corporation spends on R & D, Utica Central spends seven dollars.

9) For every vote McCormick wins in the Midwest with this new strategy, he stands to lose two or three in the Northeast and in California.

10) For every 10% increase in the value of x, y increases 25%.



Know the idioms given in bold in this post.  As always with idioms, read, read, read!   Search for the idioms in this post in context.  You understand English best when you understand it in context.


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  • Mike MᶜGarry

    Mike served as a GMAT Expert at Magoosh, helping create hundreds of lesson videos and practice questions to help guide GMAT students to success. He was also featured as "member of the month" for over two years at GMAT Club. Mike holds an A.B. in Physics (graduating magna cum laude) and an M.T.S. in Religions of the World, both from Harvard. Beyond standardized testing, Mike has over 20 years of both private and public high school teaching experience specializing in math and physics. In his free time, Mike likes smashing foosballs into orbit, and despite having no obvious cranial deficiency, he insists on rooting for the NY Mets. Learn more about the GMAT through Mike's Youtube video explanations and resources like What is a Good GMAT Score? and the GMAT Diagnostic Test.

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10 Responses to GMAT Idioms: Correlative Conjunctions

  1. Imran Malik March 31, 2022 at 3:36 am #

    Dear Mike McGarry and the Magoosh team:

    I took the full Magoosh course and read almost all of the blogs on GMAT Verbal published up to the date of my completion of the course. Mike states in this blog that the correlative conjunction “not … but” can not be used with clauses. However, Manhattan Prep in its Sentence Correction Manual Chapter 9 on idioms uses two sentences that violate this rule and highlights them as correct. Am I correct to say that the stated rule is correct and the sentences are incorrect or is there another rule that allows for their usage? Please find the two sentences:

    1. She did not eat mangoes but ate other kinds of fruits.

    2. She did not eat mangoes but liked other kinds of fruits and later began to like kiwis too.

    Thank you for your review and consideration. I sincerely appreciate your response.

    • Magoosh Test Prep Expert
      Magoosh Test Prep Expert April 22, 2022 at 11:04 am #

      Hi Imran,

      Thanks for your question! What Mike says in the article regarding “Not A but B” and other conjunctions in the same list is that “None of these are used to link two independent clauses.” In both sentences you provided, two independent clauses are not linked, so they do follow the convention Mike discussed.

      I hope this helps! Happy studying. 😀

  2. Aalekh September 19, 2018 at 7:31 am #

    Dear Mike, I saw an idiom, “Not only..but are also” in our Magoosh GMAT idioms application.

    Is the usage of are here correct?
    I think it should have been simply “not only..but also” because in the example statement are was written before ‘not’ and thus should satisfy > Once outside, twice inside < rule.

    Correct- are not only…but also..
    What do you think?

    • Magoosh Test Prep Expert
      Magoosh Test Prep Expert November 1, 2018 at 10:06 am #

      You can find a similar example of a “not only… but also” construction on this blog post: are not only difficult to memorize but are also easy to mix up.

      Note that when “not only… but also” is used, the two parts of the sentence are usually very similar in grammatical terms. For example, the sentence above can be broken down like this:

      Idioms are
      not only
      difficult to memorize
      but are also
      easy to mix up.

      So notice that here, we have the two parts “difficult to memorize” and “easy to mix up,” which both follow a very similar structure: [adjective] + “to” + [infinitive]

      When we use “not only… but also,” the two parts of the sentence tend to have similar structure like this.

      In general, the construction “not only… but also” is generally used in situations where two parts of a sentence can be expressed in ways that are very grammatically similar, so that a clear parallel structure can be created.

      hope this helps!

  3. danny August 29, 2016 at 12:24 am #

    I am confused about the last idiom
    as in your post
    “the word “for” is a preposition, so A and B have to be nouns.”
    the example you give
    ” For every 10% increase in the value of x, y increases 25%.”
    “y increases 25%” is an independent clause, instead of an noun.
    is that right?

    • Magoosh Test Prep Expert
      Magoosh Test Prep Expert September 10, 2016 at 5:49 pm #

      Hi Danny,

      You are correct that “y increases 25%” is an independent clause, but the noun that this rule is specifically referring to is “y”. B will be part of a clause, but he clause must begin with a noun. So, you can say, “for every 10% increase in the value of computers, computer batteries increase 25%.” ‘Computer batteries’ is the noun that fulfills this rule.

      • zhangshu October 2, 2016 at 12:16 am #

        hi Magoosh experts,

        I am a little confused

        For every A, B …, this construction reminded me the constructions, compared with/to A, B…. unlike/like A, B…

        my question is :
        should A and B is the same level thing, or comparable thing/people?

        is it correct, if
        For every 10% increase in the value of x, the increase in Y is 25%

        thanks a lot
        have a nice day

        • Magoosh Test Prep Expert
          Magoosh Test Prep Expert October 9, 2016 at 8:54 am #

          Hi Zhangshu,

          In many cases, you will see this idiom used with two like things (dollars spent here/dollars spent there, votes gained/votes lost.) However, this isn’t a solid rule. As long as you are comparing two things that have some sort of relationship to each other, you can use this idiom. The two things must be connected, but they don’t necessarily have to be the same.

          Here’s an example: For every dollar donated, the NGO will provide four meals to those in need. Dollars and meals aren’t the same things, but they are connected because the dollar makes the meal possible. There is a relationship, and the ratio between the two things is clearly expressed (1 dollar to 4 meals).

          Another example: For every week that an adolescent attends school every day, she decreases her chance of dropping out by 5%. Again, the relationship and ratio is apparent from the context of the sentence, even though “attending” and “dropping out” of school are opposite things!

          As for your question: remember that the ‘B’ must be a concrete noun. “The increase” doesn’t quite work here. It is better to use the construction from the blog post: For every 10% increase in X, Y decreases 25%.

  4. S87 February 14, 2016 at 5:09 am #

    Hello Mike
    Can you please explain where to use “as well as” vs ” and” ?

    For example – The university focuses on education, research and development, as well as dissemination.
    Does this mean equal focus on all 4 things?


    For example – Swedish is spoken in Sweden, as well as in parts of Finland. It means both countries speak swedish ?

    Thanks a lot

    • Magoosh Test Prep Expert
      Magoosh Test Prep Expert February 15, 2016 at 1:06 pm #

      Hi there!

      These two mean basically the same thing. The difference is stylistic.

      Swedish is spoken in Sweden, as well as in parts of Finland. –> This means that all of Sweden speaks Swedish, and parts of Finland speak Swedish also.

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