Sentence Correction (SC) | Climatic shifts are so gradual as to be indistinguishable at first fro

If another option were:
=> so gradual that they are indistinguishable

Then, how would I decide between option A and this option.
Actually, I am not clear regarding the use of so...that and so...as to. Can someone please elaborate.

Thanks

Statistics : Posted by bPra • on 16 Mar 2010, 05:05 • Replies 11 • Views 21721

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