lead
forged steel
alloy steel
aluminum alloy
第1题：
Because of the high loads the bearing material is a tin-aluminum(锡-铝) alloy bonded to a steel shell. The crosshead pin is highly polished to a______.
A.flat surface
B.mirror finish
C.sloping(倾斜的) surface
D.inclined(倾向的) surface
第2题：
Fire hose couplings ______.
A.are made of bronze brass, or soft alloy metals
B.should be painted red in order to identify hose lengths
C.are specially hardened to prevent crushing
D.should be greased frequently
第3题：
Each cylinder liner on the marine medium speed engines _____.
A.is usually cooled by sea water
B.can be replaced when worn out
C.is in direct contact with the water in the bore of the cylinder
D.can t expand when heated
第4题：
less piston slap and quieter running
increased crankshaft bearing wear
slightly greater piston wear
decreased side pressures
第5题：
Slow speed diesel engines
Medium-speed diesel engines
Steam engines
Gasoline engines
第6题：
Connecting elements of a mooring system should be fabricated from ______.
A.cast iron
B.forged steel
C.stainless steel
D.cast steel
第7题：
the extra weight required for the diesel reduction gearing
a minimum speed for the engines that limits the minimum speed of the vessel
the higher fuel consumption per SHP
the low efficiency of the system when a controllable pitch propeller is used
第8题：
To reduce the weight of the reciprocating parts, pistons of high-speed engines are made considerably shorterThis results in __________.
A.less piston slap and quieter running
B.increased crankshaft bearing wear
C.slightly greater piston wear
D.decreased side pressures
第9题：
Large crosshead type；crossheads
High speed；the cylinders
Large crosshead type；the cylinders
Four-stroke；pistons and cylinders
第10题：
reduce wear on the valve stem
permit the use of alloy valve seat materials
reduce heat transfer from the valve seat
facilitate valve removal for servicing