什么时候会在DEU上出现RF(需加油)的信息?()
A.油量等于或少于76%
B.飞机在地面
C.襟翼收起或发动机停转
D.以上全对
参考答案:D
I wonder ______, Mr.Smith. We're looking for him everywhere. [ ]
A. where has your son been
B. where your son has been
C. where have you gone
D. where your son has gone
低速磨煤机的高速电机速度降低的装置是()
A.联轴器
B.减速器
C.液力耦合器
D.皮带