Hello Everyone!

This is a great example of a IDIOM question you might find on the GMAT! Let's take a closer look at this question, one issue at a time, and narrow it down to the correct answer. To start, let's highlight the major differences between the options in orange:

Often major economic shifts are so gradual as to be indistinguishable at first from ordinary fluctuations in the financial markets.

(A) so gradual as to be indistinguishable
(B) so gradual so that they can be indistinguishable
(C) so gradual that they are unable to be distinguished
(D) gradual enough not to be distinguishable
(E) gradual enough so that one cannot distinguish them

There are two major issues we can focus on here:

1. Idioms (so gradual vs. gradual enough)
2. Wordiness (indistinguishable vs. unable to be/not to be distinguishable)

Let's start by focusing on idioms because that's the type of question we're dealing with. Here is a quick reminder of the idioms we're using:

so X as to be Y
so X that Y

Let's take a closer look at each option and eliminate any that use incorrect idioms:

(A) so gradual as to be indistinguishable --> so X as to be Y = OK
(B) so gradual so that they can be indistinguishable --> so X so that Y = WRONG
(C) so gradual that they are unable to be distinguished --> so X that Y = OK
(D) gradual enough not to be distinguishable --> X enough to be Y = WRONG
(E) gradual enough so that one cannot distinguish them --> X enough so that Y = WRONG

We can eliminate options B, D, & E because they don't use the correct idioms.

Now that we have it narrowed down to only 2 options, let's tackle #2 on our list: wordiness. The GMAT prefers options that are as concise as possible, so let's see which of these options is better:

(A) so gradual as to be indistinguishable
This is CORRECT! It uses the idiom "so X as to be Y" correctly, and it doesn't use any overly wordy phrases!

(C) so gradual that they are unable to be distinguished
This is INCORRECT for a couple reasons. First, the pronoun "they" isn't necessary here and could be confusing to readers. Second, the phrase "unable to be distinguished" is overly wordy - the word "indistinguishable" means the same thing in far fewer words!

There you have it - option A is the correct choice! It uses the proper idiom structure, and it's written using the most concise and clear language! If you can focus on the most common idioms found on the GMAT, you'll be able to answer questions like this quickly and effectively!


Don't study for the GMAT. Train for it.