This question popped up on our Ask Me Anything About SC thread, and we're reposting our answer here in case it helps anybody.
Prashilsurani wrote:
During an ice age, the buildup of ice at the poles and the drop in water levels near the equator speed up the Earth’s rotation, like a spinning figure skater whose speed increases when her arms are drawn in.
(A) like a spinning figure skater whose speed increases when her arms are drawn in
(B) like the increased speed of a figure skater when her arms are drawn in
(C) like a figure skater who increases speed while spinning with her arms drawn in
(D) just as a spinning figure skater who increases speed by drawing in her arms
(E) just as a spinning figure skater increases speed by drawing in her arms
Please help me out with this one.
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(A) like a spinning figure skater whose speed increases when her arms are drawn in
Generally speaking, we use "like" to compare nouns (i.e. "Like Tim, Mike spends his Saturday afternoons reviewing GMAT Club posts and eating grasshopper tacos." Mmm... chapulines.
).
Looking at choice (A), it seems as though we are comparing "a spinning figure skater whose speed increases when her arms are drawn in" (one big noun clause) to "the buildup of ice at the poles and the drop in water levels near the equator." That doesn't make sense because, unlike the spinning figure skater, the "buildup of ice" and "drop in water levels" don't have a
speed that increases/decreases.
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(B) like the increased speed of a figure skater when her arms are drawn in
(B) seems to compare "the buildup of ice" and "drop in water levels" to "the increased
speed of a figure skater when her arms are drawn in" -- so (B) compares the things that
affect the Earth's rotational speed to the figure skater's
speed itself, and that comparison is illogical.
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(C) like a figure skater who increases speed while spinning with her arms drawn in
(C) is out for basically the same reason as (A). Again, we are illogically comparing "the figure skater" to "the buildup of ice at the poles and the drop in water levels" (notice that "a spinning figure skater whose speed increases when her arms are drawn in" is just one big noun clause).
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(D) just as a spinning figure skater who increases speed by drawing in her arms
Choice (D) is also out for the same reason as (A). Notice that "a spinning figure skater who increases speed by drawing in her arms" is just one big noun phrase, so, again, it seems like we are illogically comparing "the figure skater" to "the buildup of ice at the poles and the drop in water levels". And even if that comparison made sense, we typically use "just as" to compare
clauses, not
nouns.
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(E) just as a spinning figure skater increases speed by drawing in her arms
All of these comparison issues are finally resolved in choice (E):
- the buildup of ice and the drop in water levels speed up the Earth’s rotation
- a spinning figure skater increases speed (of spinning)
- Both of these follow the pattern: [noun] [verb] [object of the verb]: [noun 1] speeds up [object 1] just as [noun 2] increases [object 2]
- In both cases, the nouns are what DO some action to affect rotational speed (the figure skater's spinning speed and the Earth's rotational speed). That makes it perfectly logical to compare these two clauses.
- And when we compare clauses, we want to use "as" or "just as," not "like"
So (E) is the winner.