well knurled
slightly streaked
lightly glazed
highly polished
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：
______means the curve on the earth’s surface which cuts all the meridians at the same angle.
A.Great Circle
B.Position Line
C.Rhumb Line
D.True Bearing
第3题：
A. Seen…covered
B.Seeing…covering
C.Seen…covering
D.To see…to cover
第4题：
the bearing clearances
the bearing thickness
the bearing strength
the bridge hardness
第5题：
It appears yellow.
It always remains the same.
It had a short history.
It is too cold.
第6题：
材料：
Spark erosion is caused by a voltage discharge between the main bearing and journal surface. The cause of the potential is the development of a galvanic element between the ship’s hull, sea water, and the propeller shaft/crankshaft.
The oil film acts as a dielectric. The puncture voltage in the bearing depends on the thickness of the oil film. With increasing engine ratings, the specific load in the main bearing is increased. his will reduce the oil film thickness, and enable the discharge to take place at a lower voltage level.
Since the hydrodynamic oil film thickness varies through a rotation cycle, the discharge will take place at roughly the same instant during each rotation cycle, i.e. when the film thickness is at its minimum. The roughening will accordingly be concentrated in certain areas on the journal surface. In the early stages, the roughened areas can resemble pitting erosion. but later, as the roughness increases, the small craters will scrape off and pick up white metal-hence the silvery white appearance.
Therefore, to ensure protection against spark erosion, the potential level must be kept at maximum 80 mV, which is feasible today with a high efficiency earthing device. If an earthing device is installed, its effectiveness must be checked regularly. Spark erosion is only observed in main bearings and main bearing journals.
问题：
According to the paragraph one, a voltage between the main bearing and journal surface is produced by______.
A.propeller rotation
B.leakage from M/E electric control unit
C.a galvanic element
D.friction between the main bearing and journal surface
______engine ratings increase, the hydrodynamic oil film between the main bearing and journal surface is______.A.The lower/thinner
B.The higher/the thicker
C.The lower/thicker
D.The higher/thinner
When will the spark erosion take place on the journal surface during each rotation cycle?A.when the film thickness is at its minimum
B.when the film thickness is at its maximum
C.when the engine is on its compression stroke
D.when the engine is on its exhaust stroke
During the engine room watch keeping, which equipment must be noted to ensure protection against spark erosion?A.the antifouling plant
B.the earthing device
C.the main engine electric heating coils
D.the shaft generator
请帮忙给出每个问题的正确答案和分析，谢谢！
第7题：
a restricted air intake
a clogged connecting rod oil passage
incorrect connecting rod alignment
high cylinder firing temperatures
第8题：
Serious loss of reserve buoyancy resulting from flooding any compartment of a ship will always ______.
A.increase the trim
B.change the free surface effect
C.cause a serious list
D.decrease ship stability
第9题：
the bearing near to the diesel engine
the intermediate bearing near to the thrust bearing
the intermediate bearing near to the sterntube
the bearing located at the middle of the diesel engine and the sterntube
第10题：
the equator
a loxodromic curve
a small circle
a meridian