单项选择题
A.examine the condition of the propeller B.chip and paint all hull protection zincs C.install new docking plugs in all cofferdams D.inspect the hull for hogging or sagging
Air line lubricators are used in compressed air systems...
单项选择题Air line lubricators are used in compressed air systems to lubricate （）.
A.the suction and discharge valves B.tools and equipment served by compressed air C.air line reducing valves D.all of the above
Which of the listed devices would be installed at a con...
单项选择题Which of the listed devices would be installed at a control system air pressure reducing station?（）
A.Moisture separator B.Vacuum breaker C.Lubricator D.Non-return valve
Power is defined as the （）.A.rate of doing workB.amount...
单项选择题Power is defined as the （）.
A.rate of doing work B.amount of force needed to overcome friction C.amount of work accomplished D.distance through which an object is moved
