单项选择题
A.matching pulse rates of at least 20 stations B.an automatic on-and-off switch C.a horizontal matching of all delayed hyperbolic signals D.automatic signal acquisition and cycle matching
A “figure eight” knot is used to（）.A.be a stopperB.shor...
单项选择题A “figure eight” knot is used to（）.
A.be a stopper B.shorten a line C.join lines of equal size D.keep a line from passing through a sheave
A “fifteen-pound” CO2 extinguisher is so called because...
单项选择题A “fifteen-pound” CO2 extinguisher is so called because（）.
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 “check” line is（）.A.a safety line attached to a man w...
单项选择题A “check” line is（）.
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
