相关考题
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单项选择题
The pivot pin at the base of a sheath-screw boom davit must be（）.
A.inserted each time before the booms are cranked out
B.periodically removed for inspection and lubricated
C.replaced at each inspection for certification
D.in the locked position after the boat is cradled and griped down -
单项选择题
The part of a windlass which physically engages the chain during hauling or paying out is the（）.
A.devil's claw
B.bull gear
C.wildcat
D.cat head -
单项选择题
The most serious effect of air trapped in a diesel engine jacket water cooling system is that it（）.
A.causes colloid suspension in the cooling water
B.reduces the capability of the lubrication system
C.can form pockets which block the flow of coolant through the system
D.leads to the scuffing of cylinder walls
