Since the 1930's aircraft manufacturers have tried to build airplanes with frictionless wings, shaped so smoothly and perfectly that the air passing over them would not become turbulent.
o wings, shaped so smoothly and perfectly
o wings, wings so smooth and so perfectly shaped
o wings that are shaped so smooth and perfect
o wings, shaped in such a smooth and perfect manner
o wings, wings having been shaped smoothly and perfectly so
OA B
[spoiler]Somehow when I looked at this question, I didn't even consider B as an answer choice because "wings, wings" appears to be redundant. [/spoiler]
o wings, shaped so smoothly and perfectly
o wings, wings so smooth and so perfectly shaped
o wings that are shaped so smooth and perfect
o wings, shaped in such a smooth and perfect manner
o wings, wings having been shaped smoothly and perfectly so
OA B
[spoiler]Somehow when I looked at this question, I didn't even consider B as an answer choice because "wings, wings" appears to be redundant. [/spoiler]












