A.10m B.15m C.20m D.25m
A.焊接 B.法蘭 C.絲扣 D.承插
A.聆聽油船船艙處有無異響 B.直接到油船船艙上查看 C.輕聞油船附近空氣有無異味 D.觸摸油船船艙處有無發(fā)熱