Researchers hypothesize that granitic soil is the ideal construction

I can see why people don't love A, but the "it" in A clearly refers to "soil." If you had any doubt about that, it might help to notice that "it" is already used for that purpose in the fixed portion of the sentence, and the GMAT will never switch antecedent for the same pronoun in the same sentence. In other words, once it=soil, that will remain true throughout the sentence, just like a variable in an equation.

There's also no problem with parallelism; we just shift from the simple present ("it makes") to a hypothetical ("it could cause"). It's perfectly fine to switch in this way when the meaning demands.

The odd thing is that we end up saying that the soil could make the tunnels (made of soil) collapse, but most other ways of saying this would run into problems, too. In the end, A is the only choice that works. (As others have stated, "as hard as to make" in D is not idiomatic.)

Dear Friends,

Here is a detailed explanation to this question-

Concepts tested here: Idioms + Awkwardness/Redundancy

• “enough + to” is a correct, idiomatic usage; besides, “enough” is used to show “adequacy” and generally not used to show a cause-effect relationship; rather, “so + cause + that + effect” or “so + cause + as to + effect” are some of the preferred constructions for conveying a cause-effect relationship.
• "so as to" is generally an incorrect usage; "so + cause + as to + effect" is the correct, idiomatic usage.

A: Correct. This answer choice correctly uses the idiomatic constructions “so + cause ("hard") + that + effect (”it makes burrowing difficult")" and “so + cause ("soft") + that + effect (”it could cause tunnels to collapse")". Further, Option A is free of any awkwardness or redundancy.

B: This answer choice incorrectly uses the unidiomatic construction "enough as to"; please remember, “enough + to” is a correct, idiomatic usage; besides, “enough” is used to show “adequacy” and generally not used to show a cause-effect relationship; rather, “so + cause + that + effect” or “so + cause + as to + effect” are some of the preferred constructions for conveying a cause-effect relationship.

C: This answer choice incorrectly uses the unidiomatic construction "enough so"; please remember, “enough + to” is a correct, idiomatic usage; besides, “enough” is used to show “adequacy” and generally not used to show a cause-effect relationship; rather, “so + cause + that + effect” or “so + cause + as to + effect” are some of the preferred constructions for conveying a cause-effect relationship.

D: Trap. This answer choice incorrectly uses the unidiomatic constructions "as + cause ("hard") + as to + effect ("make burrowing difficult")" and "as + cause ("soft") + as to + effect ("cause tunnels to collapse")"; please remember, "so as to" is generally an incorrect usage; "so + cause + as to + effect" is the correct, idiomatic usage.

E: This answer choice incorrectly uses the unidiomatic construction "cause ("too soft" + "so as to" + effect ("cause tunnels to collapse")"; please remember, "so as to" is generally an incorrect usage; "so + cause + as to + effect" is the correct, idiomatic usage. Further, Option E uses the passive voice construction "making burrowing difficult", rendering it awkward and needlessly indirect.

Hence, A is the best answer choice.

To understand the use of "So As To" on GMAT, you may want to watch the following video (~1 minute):



All the best!
Experts' Global Team

A) it doesn't have a clear referent
B)as to is awkward in this context
C) not parallel
E) so as to is unidiomatic

so D is the only one that survives

"so as to" is not unidiomatic. it is perfectly idiomatic. rather "as .. as to" in D is unidiomatic.

contarary to the aboves, go with A cuz "so.. that" is correct expression..

Researchers hypothesize that granitic soil is the ideal construction material for the desert tortoise because it is not so hard that it makes burrowing difficult or so soft that it could cause tunnels to collapse.

A. so hard that it makes burrowing difficult or so soft that it could cause -> Correct
B. hard enough to make burrowing difficult or soft enough as to cause -> as breaks the parallelism
C. so hard as to make burrowing difficult or soft enough so it causes -> So X as Y is not a correct idiom."as X so Y" or "as X as Y" are correct usage. Also "soft enough" breaks the parallelism
D. as hard as to make burrowing difficult or as soft as to cause -> As X as Y is used to compare the similarities about X and Y and not provide reasons. So X that Y is a better construction
E. too hard, making burrowing difficult, nor too soft, so as to cause -> Combination of idioms doesn't correct the problem

I choose A. That is the only sentence which don't have any parallel issue.
As for D, " as hard as to" is unidiomatic. I only heard of " so as to". " as hard as" can be used for comparison but then again, we run into parallel issue: it is not as hard as it is to make - we need "it is" to make the sentence parallel.

i think in D, we are incorrectly comparing soil with hardness which is incorrect. it refers to soil....as hard as to make burrowing difficult or as soft as to cause

A, is correct because it refers to soil and soil is not so hard or so soft. we do not repeat not.

hope this helps.

C. is out because hardness is compared with burrowing.

Can someone from egmat plz help here?
Isn't the use of So X As Y correct?

I think you mean "so X as to Y." That can work, although it's not the clearest way to say what we want to say. C has bigger problems, though. First, "soft enough so it causes" is not idiomatic. We need "soft enough to cause" or "so soft that it causes." Even if this were okay, it wouldn't be parallel with "so hard as."

1. (A) it doesn't have a clear referent.
What else other than 'soil' can 'it' refer to logically? Can 'it' refer to the tortoise, meaning that tortoise is not hard for X and not soft for Y? So no doubt need be entertained about the reference of the pronoun reference in A because logic is the leading light in such cases.
2. Why D is not equal to A.
D uses and infinitive as 'to make' burrowing difficult and as soft as to cause tunnels to collapse. the infinitive 'to make' implies that the action is not a finite action but at best a surmise or notion. On the other hand, A uses the subordinator 'that' using a clause with definitive action verbs 'makes' and 'could cause'. The premises of their hypothesis, in fact, are real happenings. This intention is rather feebly presented in D, making it depend upon some yet - to - happen notions rather than upon some real happenings as in A.. Therefore, it can be reckoned In D the original intent has been diluted, however grammatically normal it sounds.
Therefore, A IMO.
I have also seen that when a negative factor such as 'not' is involved, so…. as is used while in positive contexts as… as is used. Example:
Tom is not so tall as Dick
Tom is as tall as Dick.
This looks more like a convention than a decree.

generis

Can you help on this one. I got this wrong in my mock exam today.

I chose E. Comments above are saying that there is a parallelism issue. Is that so ??


Please help

warrior1991 , well, the good news is that you missed a hard question.

The posters above are correct. Option E is not parallel.
Nor is a conjunction. [That fact is easy to forget.]
Conjunctions pair equivalent things (noun phrases with noun phrases, for example).
Conjunctions are parallelism markers and join structures that are similar.

In option E, the phrases that follow too hard and too soft are not similar in structure and thus are not parallel.

(E) [G]ranitic soil is the ideal construction material for the tortoise because it is not too hard, making burrowing difficult, nor too soft, so as to cause tunnels to collapse.

Granitic soil is the ideal construction material for the desert tortoise because
IT is
NOT
-- too hard, making burrowing difficult,
NOR
-- too soft, so as to cause [tunnels to collapse]

Nor, a conjunction, signals that the two things that nor joins must be similar structures.

What structures do we have in option E? Essentially, an __ING phrase and an idiomatic clause of consequence that does not begin with an __ING word

making burrowing difficult
-- anchored by making, which in this case is a verb-like noun (in jargon, a "simple gerund." )
-- the structure is a participial phrase: [verbING] + [direct object] + [adverb]

so as to cause tunnels to collapse
-- anchored by so as to, which in this case is an idiom of consequence
-- the structure of so as to is an idiomatic conjunction that leads to a clause of consequence: [so as to] + [infinitive] + [direct object] + [infinitive modifier]

Compare the anchors.*
So as to is definitely not a verbING (a gerund).

Option E would be parallel if it were written in these two ways, the first of which is much better than the second:
. . . [the soil] is not too hard, making burrowing difficult, nor too soft, causing tunnels to collapse

. . . [the soil] is not too hard, so as to make burrowing difficult, nor too soft, so as to cause tunnels to collapse
(So as to as an idiom of consequence is rare. GMAC tends to use the construction in (A). )

Hope that helps.



*The anchors in Option A are similar.
Option A joins two parallel examples of the idiomatic structure So X that Y
so hard that it makes burrowing difficult
or
so soft that it could cause
[so] + [adjective] + [that] + [it] + [verb]
As others have mentioned, the verbs (makes and could cause) do not need to be parallel because meaning allows the verbs to be paired.
We can pair a simple present and a hypothetical: The building is sturdy and could withstand a monsoon.

DmitryFarber, EMPOWERgmatVerbal

In the discussion, it was stated that the construction "as X as Y" needs to be followed by noun. Is this really true? What about "We have as many apples as need to be cooked." I understand that the usage in D is unidiomatic but I would like to understand why or what are the rules for the usage of "as X as Y" so I don't make the same error in the future. Many thanks.

Great question @Xin_Cho!

With the construction "as X as Y," I was referring to the Y in the phrase needing to be a noun. I apologize if that wasn't clear! You are correct that your example sentence isn't idiomatically correct. While a reader can probably figure out what you're saying, there are much clearer and more grammatically correct ways to say that.

For the question we're focusing on right now, this is the construction we see in option D:

as hard as to Y

This isn't how we express that a condition is exceptionally severe, which is what the initial sentence is trying to convey. When you want to talk about an extreme condition, you would say "so X as to Y" because the word "so" emphasizes that extreme.

I hope this helps!

EMPOWERgmatVerbal VeritasKarishma GMATNinja

I understood that in the construction "as X as Y", the "Y" has to be a noun. However, in the official OG question I've encountered a problem in which this does not hold (https://gmatclub.com/forum/according-to ... 46774.html). Could I possibly ask you for an explanation?

It depends on the context. What Y can be depends on what X is.

Soil is as hard as ... (here, we need to compare the hardness of the soil with the hardness of some other substance so we can expect to have some material noun)
But we are not comparing the hardness of the soil with hardness of something else. We are talking about the degree of hardness and its impact. Hence we use
Soil is so hard that it makes burrowing difficult...


In the other question you mention,
... nearly 8 million people, about as many as ... (here we expect something that gives us the number of people)
'are enrolled in ...' gives us a number - the number of people enrolled in nation's four year colleges. Hence it is correct.

I agree with option A but my doubt here with option A is the verb of It in the last part of the sentence. "so soft that it cause". Shouldn't it be "causes" as it is singular. Moreover "so hard that it makes" also reflects its should be.. It make me think over this option longer.

Please clarify.

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