金属基底冠桥粗化处理时,用何种氧化铝砂喷砂处理
A.25~35μm
B.50~l00μm
C.35~50μm
D.100~120μm
E.15~25μm
参考答案:B
_____________ many times, the problems were settled at last.
A.Having discussed
B.Being discussed
C.To be discussed
D.Discussed
系统中变压器中性点接地方式的安排一般如何考虑?