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1.        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.

(A) wings, shaped so smoothly and perfectly

(B) wings, wings so smooth and so perfectly shaped

(C) wings that are shaped so smooth and perfect

(D) wings, shaped in such a smooth and perfect manner（B）

(E) wings, wings having been shaped smoothly and perfectly so

这题选B，我是从somothly应该修饰wings, 而perfectly说的是成形shaped选出答案的。但是没看懂这个是什么结构，为什么逗号后面还要重复一次wings？？（wings so smooth and so perfectly shaped）

大家帮忙看看，非常感谢！！