Isnt something missing in this sentence

I don't think 'flourished' is required.

in GMAT for keeping the sentence concise you don't need to use helping verbs multiple times with in the same sentence.............in Sentence Correction Manhattan GMAT guide there is a special topic based on "Brevity".......once you go through that topic, you will understand what I intend to say

Really good question, Vikram - this question bugged me the first few times I had to teach it, too.

Here's something that took me a little time to learn about the GMAT, but that I think can be extremely helpful:

When you're looking at parallel structure, it is much, much more important that the items be logically parallel than that they be perfectly, technically parallel. So...unless you see a blatant, logical parallelism error, save your parallel decision for later.

For example, you could correctly say:

Shaquille is taller than Kobe.

But GMAT students might stress this point, thinking you might need to add "is" after Kobe (Shaq is taller than Kobe is.). But there's nothing illogical about that comparison above. Since it can't really be misconstrued, the "is" is implied after Kobe, or I guess you could say it's part of the comparison itself, with "is taller than" being common to both items being compared.

Where you have a problem is if the comparison is totally illogical, like:

Shaq's height is larger than Kobe.

Here we can't compare a height to a man. That's just not logical - we need to compare height to height, so we'd need to change it to "Shaq's height is larger than Kobe's".


What you're most responsible for on the GMAT is the logic of it all - does this sentence make sound sense? I'd make my first pass through the answers one that eliminates obviously and/or logically wrong answers first, and then go back to get more technical if I have to. When you look at this question (#81 from OG10), the other answer choices all have illogical verb tenses; since we're using "at the same time as", we can't use one past tense and one present tense for these two events (e.g. "which is flourishing at the same time as the civilizations in the Nile delta did"). The wrong answers in this question are all illogical; the correct answer may not be the way you'd write it yourself, but it's logical enough that it holds up to that test, and therefore it's the correct answer (even if it's not the perfect phrasing).

isnt the comparision illogical here, correct sentence is comparing TIME with civilizations.

How about this :
Salt deposits and moisture threaten to destroy the Mohenjo-Daro excavation in Pakistan, the site of an
ancient civilization that flourished at the same time as the time at which the civilizations in the Nile delta and the river valleys of the Tigris and Euphrates flourished