电动机是否都是从0Hz开始起动？

A. -200～＋650
B. 0～400
C. 100～1000
D. 0～-200

A. 经常检查
B. 计划一实施一检查一改进
C. 实施一检查一处置
D. 行动一评审一提高

A. the solid impurities of large particle
B. the solid impurities of fine particle
C. the water content
D. both water and solid impuritie