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.
-
Awings, shaped so smoothly and perfectly
分析该选项
-
Bwings, wings so smooth and so perfectly shaped
分析该选项
-
Cwings that are shaped so smooth and perfect
分析该选项
-
Dwings, shaped in such a smooth and perfect manner
分析该选项
-
Ewings, wings having been shaped smoothly and perfectly so
分析该选项
显示答案
正确答案: B