单项选择题
The trouble-free life of an engine indicates （）.
A.the period of time during which no trouble occurs to the engine
B.no trouble will occur to the engine all its life
C.trouble may occur freely to the engine
D.no matter what you do to the engine, no trouble will occur during this period
相关考题
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单项选择题
General, the best way for replacement of lamp is （）.
A.after the point is reached at which the failures begin to increase rapidly
B.before the point is reached at which the failures begin to increase rapidly
C.before the point is reached at which the failures begin to increase slowly
D.after the point is reached at which the failures begin to increase slowly -
单项选择题
With （）, the corrosion problems are much reduced in a central cooling system.
A.no equipment in contact with sea water
B.less equipment in contact with fresh water
C.more equipment in contact with sea water
D.less equipment in contact with sea water -
单项选择题
You must take good care of the drainage cock of the air control systemBecause （） leads scale formed which might malfunction the pilot control valve and other instruments.
A.the temperature
B.the rust
C.the pressure
D.the humidity
