容量在30～70kW的电动机转子向一侧轴向窜动范围为（）.
A.1.0mm
B.1.5mm
C.2.0mm
D.3.0mm
参考答案：A
Having lived in China for 8 years, Helen has a good ____________ of both English and Chinese.
A．ability
B．guidance
C．command
D．program
下列说法中，表示气候的是：
A．暴风骤雨
B．阴转多云
C．四季如春
D．今天午后大风
