One OG verbal question

holyxie wrote:136. Although schistosomiasis is not often fatal, (it is so debilitating that it has become an economic) drain on many developing countries.
(A) it is so debilitating that it has become an economic
(B) it is of such debilitation, it has become an economical
(C) so debilitating is it as to become an economic
(D) such is its debilitation, it becomes an economical
(E) there is so much debilitation that it has become an economical

How come answer C isn't the right answer?
And what is the difference between "so...as to.." and "so that"?

remember one rule, usage of word economical is always wrong on GMAT,therefore, left with A and C

C wrong because of wrong idiom, so X [adjective] as to Y is the correct usage moreover so debilitating is it is awkward

Hey aspirant,

I'd be careful with that rule - "economical" is a legitimate word so it could certainly be used in a correct context on the GMAT. "Economic" means "pertaining to the economy"; "economical" means inexpensive or frugal...basically "cheap".

So if a question said:

For the value-conscious investor, index-traded funds are an economical way to achieve a diversified portfolio.

There's nothing wrong with that sentence - it's perfectly correct.


As for the initial question...I agree that C is awkward in a way that leads to a real lack of clarity. It's also in violation of a parallel structure:

"Although X is not Y, it is so Z as to..." would be much, much better and cleaner, so with A giving you essentially that option it's an exponentially better choice here.

But i still dont know when to use "so...as to", is it equivalent to "in order to"?