1st - i'm not quite understand why A is the correct answer - coz "at least as .. " this phrase sounds weird to me ...
2nd - i thought since "influence" is the main verb in the 1st part of the sentence, i would need "impact" verb in the 2nd sentence.
3rd - what is the correctly format - "greatly impact" or "impact greatly"


please let me know.

thanks.

(1)
that sounds weird to you? it shouldn't; in fact, it's the only way to write that construction properly!
many formal written constructions 'sound weird' because they aren't similar to the constructions used in spoken language, but this isn't even one of those. think about the following (very mundane) sentence:
the new flavor should cost at least as much as the old one.
i hope that doesn't sound wrong to you.

(2)
not necessarily - all you really need is parallelism, which dictates that whatever verb you do have should be in the present tense (like 'can influence'). all five choices have this proper tense parallelism.

(3)
in this particular sentence, neither, because it's unidiomatic to say "x impacts ON y".
in general, you could probably use either one, but the latter only if the object comes between 'impact' and 'greatly' (i.e., x impacts y greatly; you wouldn't say x impacts greatly y).

Hi Ron

The Idiom stated by you is at least as much as : as [adverb] as
But the Idiom in the question is as great an impact, second ''as' missing. Is this correct ?

Thanks and Regards,
DCE

In general, to compare two things that are equal in some respect, we use the "as (adjective) as" construction:

Chocolate ice cream is as tasty as vanilla ice cream.
I like chocolate ice cream as much as vanilla ice cream.

But we are allowed to break up the "as (adjective) as" with other words:

Chocolate is as delicious an ice cream flavor as vanilla.
You prefer vanilla, but I think chocolate is as delicious an ice cream flavor. (Note that this didn't require the 2nd "as," and is similar to the test sentence in question.)

Welcome to idiom hell. My advice is to forget everything you know or think you know about grammar and retrain your brain.

Seriously. :) There are so many idioms and you could literally spend forever trying to learn them all. Make sure you know all of the other error types cold. If you run across a particular idiom you didn't know on an OG (or other official, past test) question, write it down. Keep that list and if you see the same idiom a second time (again, from an official source), star it.

Only study the ones with the stars. Otherwise your list will be way to long. :) Also, don't put idioms on the list that you only see on our (or any other test prep company's) material. We don't have the official list that they work from, and we sometimes use things that they haven't released on an official question. (The previous "we"s refer to all test prep companies. This next one is just about ManhattanGMAT). We (MGMAT) have been making an exhaustive list of idioms tested on official, released test questions and we're going to publish this in a couple of months, when it's done. So we'll really know which ones they do test and which ones they don't. (Well, most of them, anyway - they could still test some idiom for which they haven't released a past test question.)