I can speak with some authority, now that I've taken the test for real this morning
At times I've gotten too wrapped up trying to figure out every subtle bit of idiom misuse in the English language. But in my recent preparations with actual ETS questions (forget Kaplan
and Princeton except for the mental exercise, they blow at writing test questions) -- and in lurking on this message board -- I've come to realized that it's unlikely that any question's correct answer will hinge solely
on some minor violation of an idiom. I don't think you'll miss a question just because you confuse when to say identical with
versus identical to
What seems more common is that unidiomatic usage is just clue #1, and that there's at least one other major problem with the distractors.
....something to keep in mind if you're killing yourself trying to master the little idioms.