Sentence Correction

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
B. hard enough to make burrowing difficult or soft enough as to cause
C. so hard as to make burrowing difficult or soft enough so it causes
D. as hard as to make burrowing difficult or as soft as to cause
E. too hard, making burrowing difficult, nor too soft, so as to cause


What is wrong with option D?

abhasjha wrote: What is wrong with option D?

Clay is not as hard as cement.
Conveyed meaning:
Clay is not as hard as cement [is hard].
The words in brackets are omitted, but their presence is implied.

D: Granitic soil is not as hard as to make burrowing difficult.
Conveyed meaning:
Granitic soil is not as hard as to make burrowing difficult [is hard].
The implied comparison makes no sense.
Eliminate D.

thank you mitch.

I thought

"So hard that" was wwong, I thought that the correct way to use 'so' was in the format "so ... as to ...". Am I wrong? When can I know which to use?

Thanks

renatofarias wrote:I thought

"So hard that" was wwong, I thought that the correct way to use 'so' was in the format "so ... as to ...". Am I wrong? When can I know which to use?

Thanks

"So x that y" is definitely a valid construction.

"So x as to y" isn't technically wrong, but GMAC seems to have a complicated stance on. (In an earlier OG, an answer choice was deemed wrong because it contained the construction. In a later version, the correct answer actually contained it. The GMAT tends not to depart from common usage, and my go-to usage guide deems "so...as" to be perfectly acceptable.)

My advice: don't use this split as a decision point. There will be other differences among the answer choices and other elements of the incorrect options that are definitively incorrect.