Why didn't I get this SAT writing question right?

Lagging
Thu, 30 Aug 2012 02:47:57 +0000

Wording preference has no place in the SAT. Often there are multiple ways of wording something (where vs in which) but both are grammatically correct. Therefore, while your solution works within the sentence, there was no error to begin with. An error is different than wording preference. If there’s no error then you shouldn’t change things even if it sounds “better” your way.