Let's start with this simple example:

• "Bob's fur is brown." - "fur" is a noun, so we use the possessive "Bob's" to qualify that noun

Now consider these two options:

• "Bob barking is keeping me awake."
• "Bob's barking is keeping me awake."

Which is correct? Well, in this case, "barking" is acting like a noun (it's a gerund, if you like the jargon). Just as we need the possessive form when we write, "Bob's fur," we need a possessive to qualify "barking". So the first option is incorrect. "Moon rising" in (C) has the same problem.

And if you're looking for another reason to give (C) the boot, it uses an illogical idiom: "A newly installed radar warning system mistook the moon rising to a massive missile attack..." I can mistake one item for another, but I can't mistake one item to another. You don't have to memorize the idiom; you just need to recognize that the construction in (C) makes it sound as though the warning system is incorrectly transporting the "moon rising" to a "missile attack," which is utter nonsense.

I hope that helps!
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The correct idiom tested here is "mistake/mistook X for Y". This immediately rules out A, C and E.
B is correct because the comparison is between the event - rising of the moon - and -massive Soviet missile attack". The comparison is not between the moon and the missile attack or the moon and a missile.

Mistook X for Y is the correct idiom.

Elim everything but B and D.

D: awkward and illogical. The radar system mistook the rise of the moon, not exactly the moon itself.

I agree B. The reason why D is wrong is that "moon as it was rising for" suggests that the moon was rising for the sake of "massive Soviet missile attack". For example:

Tom would do anything for her-----> the "for" here has the same logic as that in option D

Only two close answers are A & B

(A) rising of the moon as a massive missile attack by the Soviets
--Mistook X as Y is incorrect use of idiom.
(B) rising of the moon for a massive Soviet missile attack
-- Correct. Idiom Mistook/Mistake X for Y is correctly used here.

Hence choice (B) is the answer.
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Dear Expert,

May I ask whether "moon rising" and "rising of the moon" are interchangeable? Thanks!

I am not an expert but I’d like to share my thoughts:
“The rising of the moon” is a noun phrase in which the noun is “the rising” and “of the moon” is a prepositional phrase that modifies the noun.
“The moon rising” is also a noun phrase in which the noun is “the moon” and the present participle “rising” modifies the noun.

The intended comparison is between the event of rising (of the moon) and the attack (of the Soviet missile). I think about the word “attack” and gets that it is an action that is abrupt at first and then progressive. This non-static nature is also seen in the word “rising”. Thus, "rising" and "attack" are in perfect parallel to each other.

If we use “moon rising”, the comparison is now between the moon and the attack -> not convey the intended meaning.
Hope that helps!

Posted from my mobile device
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Thank you Tracy95, that makes sense!

Thank you GMATNinja. That helped. Although I do feel uneasy since in some distant part of my memory I think that there were times that it's ok to use that gerund as a noun. How about a sentence like this?

"Him talking to me makes me feel sick"
What about "Jim talking to me makes me feel sick"? Would it be fine or should it have been "Jim's talking to me makes me feel sick?"

Thanks!

"Him talking to me makes me feel sick" - Here, "talking" is a gerund and acts like a noun! Think of a stripped down version of this sentence: "Talking makes me sick." The subject is "talking" (a noun) and the main verb is "makes".

Back to your example: whose talking makes me feel sick? HIS talking. Just as we needed the possessive form when we wrote, "Bob's fur" above, we need a possessive to qualify "talking".

You wouldn't say, "Bob fur is brown." For the same reason, "Jim talking..." or "him talking..." would be incorrect in your examples.

I hope that helps!
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how to distinguish in meaning between these two,
(A) rising of the moon as a massive missile attack by the Soviets(looking soviets attack with the missile)

(B) rising of the moon for a massive Soviet missile attack(here Massive Soviet Missile Attack...looking like some big soviets(may be name of missile or country missile attack.) or size of soviets.
its like (massive asteriod moving toward earth.)

Consider two examples:

1) Tim, who has begun to experiment with psychedelics when his kids are asleep, saw the rising of the moon as a missile attack by the Soviets.

Here, poor drug-addled Tim seems to believe that the Soviets are using the moon to attack America! (This is particularly remarkable considering the Soviet Union's current position in the geopolitical order.)

2) Tim, who has begun to experiment with psychedelics when his kids are asleep, mistook the rising of the moon for a missile attack by the Soviets.

Now Tim doesn't believe that the Soviets are using the moon to attack America. Rather, when he saw the moon rising, he mistakenly thought he was witnessing a Soviet weapon, perhaps a spherical, pock-marked nuclear warhead that arguably resembles cheese.

While Tim is not exactly dazzling us with his observational acuity here, the second scenario seems more plausible than the first one.

I hope that helps!
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Dear Friends,

Here is a detailed explanation to this question-



Choice A: This answer choice employs the unidiomatic phrase "mistook the rising of the moon as"; the correct form of this phrase is "mistook the rising of the moon for". To simplify further, the correct form of this idiom is "mistake/mistook X for Y". Thus, this answer choice is incorrect.

Choice B: This answer choice is perfectly idiomatic and conveys the intended meaning of the sentence. Thus, this answer choice is correct.

Choice C: This answer choice also makes the mistake of not utilizing the correct idiom form "mistake/mistook X for Y". Thus, this answer choice is incorrect

Choice D: This answer choice changes the meaning of the sentence by employing the phrase "moon as it was rising"; the intended meaning of the sentence is that the radar mistook the moon's action of rising for a missile attack, not that the radar mistook the moon itself for the attack. Thus, this answer choice is incorrect.

Choice E: This answer choice repeats the error found in Option A. Thus, this answer choice is incorrect.

Hence, B is the best answer choice.

All the best!
Experts' Global Team
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Dear GMATNinja,

I've just learned about appositive modifier and the construction noun + noun modifier today. It led me to thinking, how about "him talking" is a noun + noun modifier? What about this sentence: "I can't imagine him talking to me" then "him" is a noun, and "talking to me" is a Verb-ing modifier?

"One automobile manufacturer has announced plans to increase the average fuel efficiency of its sport utility vehicles by 25 percent over the next five years, an increase amounting to roughly five miles per gallon, and representing the first significant change in the fuel efficiency of any class of passenger vehicle in almost two decades."

"an increase + amounting" to can be similar to "him + talking to me", no?

Another example would be "The list containing only two sets of names surprises me." In this sentence, "containing only two sets of names" is a modifier that modifies "the list"

I guess my question is then, how is that sentence different from "Bob barking is keeping me awake." Can "barking" be a modifier that modifies "Bob"?

Thank you! I appreciate your patience!

It's a question of what exactly is keeping you awake:

• "The dog's barking is keeping me awake" - Here, the BARKING is the thing that is keeping you awake. So "barking" is the subject, and "dog's" essentially modifies that subject.
• "The barking dog is keeping me awake." - In this case, DOG is the subject, and "barking" modifies "dog". Which dog? The barking dog.

And notice that the modifier "barking" comes before "dog" in the last example (you wouldn't say "the dog brown is keeping me awake", right?). If you want "barking" to modify "dog" but want "barking" to come after "dog", you'd probably have to do something this: "The dog, barking at the top of his lungs, is keeping me awake." In this case, we're saying what the dog is DOING. You certainly wouldn't say, "The barking at the top of his lungs dog is keeping me awake."

Similarly, you would say, "... a shocking increase in price...", not "... an increase shocking in price...".

Back to choice (C): if we wanted "rising" to modify moon, we'd probably need to say something like "...mistook the moon, rising over the ocean, AS a massive missile attack..." Also, notice that this changes the meaning: now it isn't the RISING of the moon that is being mistook for a missile attack. Instead, it's the MOON ITSELF that is mistaken for a missile attack.

The takeaway: there is no point in trying to memorize constructions and blindly apply them to new problems. You have to think really hard about each individual sentence: what's the noun? What's the modifier? Do they make any sense? Is the logical meaning clearer in another option?

This is what makes GMAT SC so hard, and unfortunately the only way to become GREAT at it is to think really literally and methodically about meaning in each specific case. Broad grammar rules are valuable, but they won't get you all that far by themselves.

For more on that, check out the our SC guide for beginners or this rant about how to improve from great (760) to incredible (780!) on SC.

I hope that helps a bit!
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This question tests the idiom ‘mistook X for Y’

We need to look for an option that uses the right idiom.

Let’s scan the options:

(A) rising of the moon as a massive missile attack by the Soviets

(B) rising of the moon for a massive Soviet missile attack

(C) moon rising to a massive missile attack by the Soviets

(D) moon as it was rising for a massive Soviet missile attack

(E) rise of the moon as a massive Soviet missile attack

Eliminate Options A, C and E.

Option D says ‘it was rising for a massive … attack’ – which honestly does not make a lot of sense.
The incorrect comparison in D leads to this illogical meaning. Eliminate.

Option B is the best choice.

Hope this helps!
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Concept tested : Idioms
Correct form "Mistook X for Y"