yeah,but remember one thing: the objective of SC in gmat is to know how well test takers understand the meaning of a sentence which is expressed in formal and concise English, as well as how well they master the usages of English.
At least we can make sure that No.2,7,10,11 sentences are correct,
No.2 Because young children do not organize their attention or perceptions systematically, as adults do, they may notice and remember details that their elders ignore. (a comma before "as adults do")
No.7 Because young children,unlike adults, do not organize their attention or perceptions systematically, they may notice and remember details that their elders ignore.
No.10 Young children may notice and remember details that their elders ignore, because they, unlike adults, do not organize their attention or perceptions systematically.
No.11 Because young children do not organize their attention or perceptions as systematically as adults do, they may notice and remember details that their elders ignore.
And No.3,4,5,8 are definitely wrong.
And No.1,6,9 are not formal, and we'd bettter not take them as good sentences in Gmat.
This is the "like" vs. "as" lesson - be careful, because we all mess this one up in everyday English:
"like" is used to compare nouns. Just nouns - nothing else.
"as" is used to compare clauses (ie, a phrase that includes a verb - could include a noun, too, but has a verb)
We have defaulted, in spoken English, to using "like" all the time - but we're speaking incorrectly when we do so.
So, logically, the sentence is not just comparing children to adults, but what children don't do to what adults do. Children don't organize systematically. Adults do organize systematically. Because the verb is part of this comparison, we have to use "as."
And we can't just use the "as" - we have to say "as adults do" b/c, again, we're comparing the verb.
A "like" sentence might say: Bobby's eyes, like those of his brother Peter, are blue. I'm not comparing "are blue" to something else - in fact, there isn't even another verb in the sentence to compare with. Here, I really am just comparing Bobby's eyes to Peter's eyes (just nouns), so I use "like."
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Stacey Koprince
GMAT Instructor
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Manhattan GMAT