礼节性拜访不宜逗留太久，一般以（）分钟为宜，即可告辞。 ["十五分钟","三十分钟","六十分钟","九十分钟"]
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）. ["oil foaming in the compressor","higher than normal suction and discharge pressures with a higher box temperature","higher than normal discharge pressure with a normal box temperature","the compressor to run continuously"]
在领导人的类型中，第四代领导是（）。 ["顾问式领导","教练式领导","管控式领导","带动式领导"]
中国银行中小企业的品牌主题是（）。 ["A.成长有期，价值无限","B.知你所需，伴你成长","C.您的关注，我的祝福","D.比您更关心您"]
试述熔断器的结构原理？
漏电保护器的特性包括哪些方面？
