企业法人只准使用（）个名称。 ["2","1","3","4"]
Brushless generators are designed to operate without the use of（）. ["brushes","slip rings","commutators","all of the above"]
The reference datum used in determining the heights of land features on most charts is（）. ["mean sea level","mean high water","mean low water","half-tide level"]
根据《建设项目安全设施“三同时”监督管理办法》，跨两个及两个以上行政区域的建设项目安全设施“三同时”由其实施监督管理。
检务档案保管期限：一般出境检验检疫档案为（）；入境检验检疫档案为（） ["三年；四年","二年；三年","四年；三年","三年；二年"]
发电机负序电流有哪些危害及其特点？怎么防止？
