（） the supercharge pressure is, （） power an engine develops.

[单选题]The power transformer is used to change( )of the power grid for the purpose

[单选题]If the suction pressure at the refrigeration compressor is below normal, the cause can beA．refrigerant overchargeB．overfeeding by the expansion valveC．a restricted suction strainerD．due to short cycling of the compress

[单选题]If the head pressure of a reciprocating refrigeration compressor is excessiveA．the relief valve should open before the high pressure cutoutB．the relief valve should open and allow the excess refrigerant to flow to the receiverC．the high pressure cuto

[单选题]The pressure differential across a diesel engine lube oil system duplex filter should be checked to ________.A．determine the need for filter cleaningB．measure any change in oil viscosityC．prevent damage to the filterD．determine the need for batch fil

[单选题]Loss of lubricating oil pressure to the main propulsion diesel engine will actuate a/an _____.A．over-speed tripB．audible/visual alarmC．the ships/boats general alarmD．reserve oil storage tank

[单选题]The pressure ________ causes Americans选择Thepressure________causesAmericanstobeenergetic,butitalsoputsthemunderaconstantemotionalstrain.A．)tocompeteB)competingC)tobecompetedD)havingcompeted

[名词解释] 水压力（hydraulic pressure）

[单选题]As a high pressure system approaches，the barometer reading（）.A . stays the sameB . fallsC . risesD . falls rapidly

[单选题]The highest pressure in a diesel engine cylinder normally occurs （）.A . at TDCB . before TDCC . after TDCD . during air starting

[单选题]An increased pressure differential between the inlet and outlet of a strainer usually indicates the strainer is （）A . holedB . fouledC . cleanD . dry