三相电路与单相电路比有什么优点?
参考答案:
发电方面可提高功率50%;输电方面节省钢材25%;配电方面经济且便于接入负载;用电方面结构简单成本低、运行可靠、维护方便。
Imagine how excited we were ____ that our schoolmates had been admitted to some famous universities.
A.learning
B.having learned
C.to be learning
D.to learn
日常肮空天气报告中,能见度电码“9999’’表示的是().
A.能见度≥lO千米
B.能见度大干1O千米
C.能见度为9999米