GWD TN16-Q41 as... as结构

tintinc

41. GWD-23-Q13
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

答案A。平行上来说D明显结构要比A清晰，不选D，D错在哪里呢？
谢谢！

cycyang

若用as hard as结构，找不到比较的对象，as前面是granitic soil, 后面呢（理论上应该另外一种土壤）？as soft as也找不到比较对象。

tintinc

谢谢cycyang。

我稍微总结一下我的盲点，请指教！
1. as... as永远是比较结构（和so as to无关），前后要有比较对象，否定句中so... as也可，但是as... as优先
2. so that只能用so... as to解释，后者严格要求逻辑主语一致。

最后，这句话是结果状语吗？makes怎么看怎么不舒服。。。

cycyang

Your summery seems to be quite good. Hope it is useful for your future practice. In fact, I am not good at summerizing the imformation and more often I follow my feelings for the answer.

"it is not so hard that it makes burrowing difficult or so soft that it could cause tunnels to collapse."

这里应该是结果状语从句吧，前面用it makes说明如果土壤太硬，就能造成这个结果，陈述一个事实。而后面用could cause，是在说有坍塌的可能性。

tintinc

But GMAT is more rational than emotional and I cannot rely solely on my feelings:S

Another question, so, if change the two "as" in D into "so", is it correct?