A.10S B.20S C.30S D.40S
A.先關(guān)掉港方的閥門,后關(guān)掉船舶出口閥 B.同時(shí)關(guān)掉港方的閥門及船舶出口閥 C.后關(guān)掉港方的閥門,先關(guān)掉船舶出口閥
A.28 B.60 C.61 D.65