A.先高壓后低壓 B.先低壓后高壓 C.先簡(jiǎn)后難 D.無(wú)所謂
A.60s B.30s C.90s D.120s
A.關(guān)閉入口門 B.關(guān)閉出口門 C.立即合閘啟動(dòng) D.無(wú)影響