A.there are fifteen pounds of CO₂ in the container
B.the container，when full，weighs fifteen pounds
C.the pressure at the discharge nozzle is l5 psi
D.the empty container weighs fifteen pounds

A.a safety line attached to a man working over the side
B.used to measure water depth
C.used to slow the headway of a barge
D.used to measure the overhead height of a bridge