题目内容
一般电气设备的额定电压为220V/380V，一般要经过一级降压，才能送到用户使用。
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闭环环式供电要求两回路之间的连接设备开关性能不高，因此安全性常常不能可靠保障，常多采用开环方式。
One of the greatest achievements of the later 20th century was a huge increase in life expectancy.
Some of the reasons for this were the development of antibiotics, having a supply of clean water, having a better system for removing dirty water and the improvement in living standards.
1Time-poverty syndromeThis health hazard is caused by trying to do too much in too little time. Many people feel that they are never in control of their lives. This can cause stress, depression and finally burnout.
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