A.5% B.10% C.15% D.18%
A.發(fā)出斷線信號(hào) B.發(fā)出信號(hào),斷開保護(hù)電源 C.斷開保護(hù)正負(fù)電源 D.無(wú)任何信號(hào)
A.40% B.80% C.20% D.95%