飞机的纵向和方向稳定性之间().
A、互相独立
B、必须匹配适当
C、纵向稳定性好,方向稳定性就差
D、方向稳定性好,纵向稳定性就好
参考答案:A
Due to the heavy rain and flooding, ten million people have been forced ________their
homes. [ ]
A. leaving
B. to leave
C. to be left
D. being left
双速异步电动机是通过改变定子绕组的接线方式以改变(),从而实现双速运转。
A.绕组上的电压
B.电源频率
C.转差率
D.磁极对数