66, Since the 1930's aircraft manufacturers have tried to build airplanes wiht frictionless wings, shaped so smoothly and perfectly that the air passing over them would not become turbulent.
B. wings ,wings so smooth and so perfectly shaped
答案:B,请问A为何不好?B中smooth 修饰shaped 不太对啊?
70, Unlike that of human beings ,who waste away when they go without food for long periods, hiberanting bears exist for months on only their excess fat.
B. Unlike human beings, who waste away when they go C. unlike human beings, wasting away when going