以下哪个不是主飞行操纵系统？
A、扰流板
B、升降舵
C、副翼
参考答案：A
—The book is very interesting.
—Yes. And you can______ one______the bookstore. [ ]
A. buy; from
B. sell; to
C. buy; to
D. buys; for
教育的社会化功能
