A.a not knowing B.an unknowing C.an unknown D.a not known
A.positive correction B.dip error C.negative correction D.semidiameter error
A.break glass，pull valve，break glass，pull cylinder control B.sound evacuation alarm，pull handle C.open bypass valve，break glass，pull handle D.open stop valve，open control valve，trip alarm
A.that the fuel valve is open B.if the air supply system is open C.if the water sprinkler system is open D.if the limit switch is on
A.radial B.sheath-screw C.gravity D.quadrantal
A.camel B.dolphin C.rat guard D.wedge
A.brake B.devil's claw C.pawls D.All of the above
A.actual depth of water B.actual depth of water below keel C.average depth from waterline to hard bottom D.average depth of water to soft bottom
A.fairlead B.heaving line C.stay D.warp
A.Globe valve B.Butterfly valve C.Gate valve D.Packless valve
