Sentence Correction

I had a request to answer this one. This question is from GMATPrep.

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 indistinguishable
E) gradual enough so that one cannot distinguish them

The issues here are IDIOMS, MEANING, and CONCISION.

A) so gradual as to be indistinguishable
"so... as to be..." is a correct idiom.

B) so gradual so that they can be indistinguishable
"so... so that..." is not a correct idiom

C) so gradual that they are unable to be distinguished
This one is tough, because it's not grammatically or idiomatically incorrect. "So... that" is a correct idiom. It's certainly wordier than A, and there also seems to be a disconnect in meaning. If something is "indistinguishable," then people are not able to distinguish it. Here, saying that the "shifts... are unable to be distinguished," then the lack of ability is on the part of the shifts, and not on the people distinguishing. This is a case in which passive voice alters the meaning slightly, and therefore makes less sense.

D) gradual enough not to be indistinguishable
"gradual enough" means something different from "so gradual." "Enough" implies a sufficient quantity, above a certain threshold - "I have enough money to by the new laptop." "So" is a qualifier meaning "to such a degree that." For example, "I have so much money that I could buy all of the laptops in the world." It doesn't imply any threshold.

E) gradual enough so that one cannot distinguish them
Same issue as in D.

The correct answer is A.

gmat_for_life wrote:Thanks a lot Celilidh for your detailed analysis!

So if I'm able to understand option C correctly, its basically telling that the 'economic shifts' are not able to distinguish themselves. Is that correct?

Regards,
Amit

Exactly right!

aflaam wrote: Is it correct that GMAT prefers so to enough?
Best,

That really depends on the context. "Enough" is perfectly correct when the intended meaning is having reached a sufficient threshold.

Here's an example of when "enough" was correctly used in OG 2015 #99. Notice that "enough" is outside of the underlined portion:

The stars, some of them at tremendous speeds, are in motion just as the planets are, yet being so far away from Earth that their apparent positions in the sky do not change enough for their movement to be observed during a single human lifetime.

If the the choice is between "so" and "enough" when the intended meaning is "to such a degree that," pick "so."

Nina1987 wrote:Ceilidh,

GMAT seems to be particularly fond of this idiom. Here is another official example where this idiom appears in correct choice. -
The Emperor Augustus, it appears, commissioned an idealized sculptured portrait, the features of which are so unrealistic as to constitute what one scholar calls an "artificial face."
(A) so unrealistic as to constitute
(B) so unrealistic they constituted
(C) so unrealistic that they have constituted
(D) unrealistic enough so that they constitute
(E) unrealistic enough so as to constitute

I think what they do here is - have this slightly uncommon but correct idiom in the correct choie and have a more popular so..that in an incorrect choice and thus lure a test taker into choosing a wrong answer.
What do you think?

Sharp observation! You'll start to notice as you study that GMAT test writers have favorite idioms, and favorite ways of tricking your ear. This certainly seems to be one of them.

In this example, "so unrealistic that they constitute..." would have been perfectly correct, but that wasn't an option. Often, test-takers have an "ideal" version of what they want the answer to be, and will pick the closest answer to it. C would be the trap for that. Instead, we should evaluate each answer choice and ask "is there an error in grammar or meaning?" rather than asking "what would I want it to say?"