关于新东方语法分册习题来源的疑问

cjkiara

有人上过新东方GMAT 的强化班吗？其中商学院入学指导的语法分册上面有好多题我错的都不明不白的，由于没有讲解，求各位好心的哥哥姐姐帮我解答一下，不胜感激。。。
Part two.88. since the 1930’s aircraft manufactures have tried to build airplanes with 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
C. wings that are shaped so smooth and perfect
答案是B，但是我选了C

cjkiara

ps：有没有人得到过关于这个语法分册的详细讲解啊~~~

walt77

其实这本书的来源都是 prep og gwd...大全。lz还是做 prep 08 吧~ 别看这个没解释的了！