对一类负荷如何供电。（）
A、两个独立电源
B、专用线路
C、单回路
D、ABC都对
参考答案：A
It's so kind of you to help us. Without your help, we couldn't have finished the work___________.
[ ]
A.in a time
B. at no time
C. ahead of time
D. behind time
一期愈合与二期愈合的主要区别是什么？
