主要由壳体、叶轮、导流器、磁电转换器、前置放大器组成的流量计是（）流量计。
A、涡街
B、涡轮
C、旋进旋涡
D、电磁
参考答案：B
To learn to speak English well,_____.
A．much practice is needed
B．one needs much practice
C．much practice is needed by one
D．one is needed much practice
木瓜具有的功效是（）
A.祛风除湿，清湿热
B.祛风除湿，止泻痢
C.祛风除湿，止痛解表
D.祛风除湿，散寒止痛
E.舒筋活络，和胃化湿
