组合舵在舵叶上下两端各安装一块制流板的作用：（）
A.减少绕流损失，改善舵的流体动力性能
B.保护舵叶
C.便于安装拆检
D.增加强度
参考答案：A
Sorry， I didn’t hear you. I to the music.
A．just listened
B．was just listening
C．has just listened
D．had just listened
ry， I didn’t hear you. I to the music.