Excessive vibration of an automatically fired auxiliary boiler can be caused by （）

[名词解释] 英译汉：vibration

[单选题]A governor automatically controls engine speed by regulating （）.A . fuel supplyB . firing orderC . engine loadD . oil level

[单选题]An electrically driven automatically operating auxiliary blower is provided for slow speed and （） of a low speed diesel engine.A . manoeuvring operationsB . bad combustionC . coolingD . mooring trial

[单选题]To prevent excessive __ in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possibleA．thermal stressesB．bending momentsC．thermal loadsD．surface tensions

[单选题]To prevent excessive __ in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possibleA．thermal stressesB．bending momentsC．thermal loadsD．surface tensions

[单选题]Excessive alkalinity of the water in an auxiliary boiler can cause （）.A . caustic embrittlement of the boiler metalB . acidic corrosion of the boiler metalC . hard scale deposits on the boiler tubesD . etching of the heat exchange surface

[单选题]Excessive clearances in the main or crank-pin bearings will sometimes be indicated by （） before any bearing knock is heard.A . loss of flow in the fuel systemB . loss of pressure in the air systemC . loss of flow in the lubricating systemD . loss of

[单选题]E．xcessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur when the compressorA．has run continuously for a long periodB．suction pressure is below normalC．oil level is below normalD．starts after a long idle period

[单选题]In a diesel engine, excessive cylinder liner wear will cause （）(1) increased blow-by(2) wear between the piston ring and grooveA . (1) only is correctB . (2) only is correctC . both (1) and (2) are correctD . neither (1) or (2) axe correct

[单选题]What effect does excessive positive ions have on some people?A．They think they are mad.B．They feel very tired.C．They become violently sick.D．They are too tired to do anything.