GMAT Prepositions and Idioms: “for”

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

Prepositions in English display a powerful diversity of uses.  In previous preposition article, we talked about the proposition “of”.  Here, we will look, at the preposition “for.”


The preposition “for”

The word “for” is a preposition.  This means, it must be followed by a noun — or by something playing the role of a noun.   This latter category includes gerunds and substantive clauses.

1) Someone who doesn’t understand baseball well is likely to mistake running as part of a hit-and-run play for stealing a base.

2) The teachers chaperoning the dance are not responsible for whatever may happen on the way home afterwards.

In sentence #1, the object of the preposition “for” is a gerund phrase, and in sentence #2, the object is a substantive clause.   Incidentally, both of these are exemplary of idioms involving the word “for.”


Fundamental uses of “for”

First of all, the word “for” can be used in an indirect object construction, and so one can “do a favor for someone“, “say a prayer for someone“, “bake a cake for someone“, etc.   This construction tends to arise in either narrative or in informal day-to-day conversation, so it is unlikely to appear in the academic and professional passages on the GMAT.  Nevertheless, this structure gives a hint to some of the core meanings of its uses.  If one is “for a cause”, then one supports that cause and is in favor of it.   Many of the uses of “for” carry this supporting or favorable connotation.


Verbs requiring “for”

Two verbs with idioms that require a “for” prepositional phrase are

argue for

allow for

The structure argue for is very much in line with the “for a cause” idiom mentioned above.   If I argue for X, that X is some position or perspective or opinion or point-of-view that I support.

3) The senator argued for naming the new veteran’s hospital in his state after Omar Bradley.

The opposite idiom — if one person argues for X, then his opponent may argue against X.   The prepositions “for” & “against” form a natural pair of opposites.

The structure allow for is far more complicated and subtle.   One use is the structure P allows for Q, where P is a law or set of rules and Q is some activity or specific case consistent with these rules.

4) The First Amendment allows for free speech, even speech critical of the government.

5) The Heisenberg Uncertainty Relation allows for momentary violations of fundamental laws of Physics, such as Conservation of Energy.

A second use is to allow X for Y, where X is some resource (time, money, room, etc.) needed to accommodate Y.

6) The county budget does not allow any additional funds for unemployment services.

7) After beginning construction, the developer discovered that the state’s water allocation system would not allow sufficient drinking water for his planned housing development.

8) Baseball’s unique structure allows essentially unlimited time for the resolution of events at the end of a game.

A more abstract use of this idiom to allow for J has the meaning: to acknowledge extenuating conditions, to give consideration to contingencies.   In this construction, J is the quality or characteristic that would excuse or provide mitigating conditions for someone.

9) Allowing for the young person’s rash judgment, the police decided to drop all charges.

10) The career numbers Ted Williams produced are even more extraordinary when we allow for his two long stints in the armed services during his prime.

Three further verbs form a set of related idioms involving “for”

substitute A for B

mistake A for B

sacrifice A for B

In all three, A is someone or something that “takes the place” of B.   When we say we are going to substitute A for B, we are saying that, in some context, we will replace B with A.  This is precisely how we use the terminology in math: “substitute (2x + 7) for y.”  We use it with the very same meaning in any one of a number of other contexts:

11) On the World Series roster, the manager substituted a rookie for the injured veteran.

12) She substitutes maple syrup for cane sugar in her muffin recipes.

13) Critics of the Soviet Union argued that the Bolsheviks merely substituted one oppressive despotic system for another.

Notice, incidentally — when we substitute A for B, B is gone and A is part of the final product, but when we replace A with B, A is gone and B is part of the final product.

The idiom to mistake A for B is like a “substitution” that happens entirely in one person’s head.   If I mistake A for B, then A is the real person or situation at hand, and through my mistake, I don’t recognize A — for whatever reason, I instead am under the mistaken impression that B is at hand, rather than A.

14) The students, seeing an image of Henry David Thoreau, mistook him for Lincoln.

15) The inexperienced investors mistook a short-covering rally for a major upturn in the market.

The idiom to sacrifice A for B also is like a kind of substitution.  In this idiom, A is the resource or asset that one gives up, with the specific intention of attaining B, some desired condition or result.

16) The executive was not willing to sacrifice his integrity for the lucrative deal.

17) In the hindsight of history, Neville Chamberlain is seen as having sacrificed the Sudetenland for what he naively thought would be “peace for our times.”

18) The think tank’s paper argued that the federal debt, in effect, sacrifices the prosperity of future generations for our own unbridled consumption.



This idiom is an example of the same root word taking the same preposition in different forms.  Both the noun responsibility and the adjective responsible take the preposition “for”

responsibility for

responsible for

In both cases, the agent who “is responsible” or who “has responsibility” is the person/thing on whom events depend, and the object of the preposition “for” is the process or event  or person or thing that the subject controls or influences.

19) The President is ultimately responsible for the actions of the entire Executive Branch of the government.

20) While the Moon’s gravitation is responsible for the overall cycle of the tides, the Sun’s gravitation is responsible for the difference between spring tides and neap tides.

21) Patients’ rights groups complained that the proposed medical malpractice reform essentially would absolve doctors of any responsibility for their professional decisions.


For every A, B

This idiom is unique.  In a way, this is a grammatical idiom that derives from formal logic.   When we say For every A, B, we are saying that A is some category with multiple members, and for some reason (legal or mathematical or scientific or …), we know that for each member in this category, B is true.   Sometimes it is used to express ratios in a population (“For every 3 people who do X, 7 people do Y.”)

22) For every high school baseball player who eventually rises to a career in the Major League, more than 360 other high school baseball players never go so far.

23) Because of the dominance of matter over antimatter, at least in our Solar System, some theoretical physicists doubt that there truly is a positron for every electron.

24) The Fundamental Theorem of Arithmetic states that for every natural number, the number’s prime factorization is unique.



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.

4 Responses to GMAT Prepositions and Idioms: “for”

  1. Hets October 14, 2014 at 6:32 am #

    Hi Mike,

    What is the difference between ‘responsible for’ and ‘responsible of’?


    • Mike MᶜGarry
      Mike October 14, 2014 at 10:16 am #

      Dear Hets,
      I’m happy to respond. The construction “responsible of” is 100% incorrect: that is not a correct idiom in any context. The idiom “responsible for” is correct and widely used. I am “responsible for” something (my job, a child, a pet) if I have to take care of it or tend to it in some way.
      Does this make sense?
      Mike 🙂

      • Hets October 15, 2014 at 12:17 am #

        Got it! Thanks Mike 🙂

        • Mike MᶜGarry
          Mike October 15, 2014 at 10:18 am #

          You are quite welcome. 🙂 Best of luck to you, my friend.
          Mike 🙂

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