How does combustion air enter the cylinder of a two-cycle diesel engine?（）

[单选题]Combustion knock can occur in the cylinders of a diesel engine under any condition permitting （）.A . a shortened ignition delay periodB . a lean fuel/air mixtureC . excess fuel in the combustion chamberD . rapid vaporization of injected fuel droplet

[单选题]Diesel engines obtain combustion air through turbo chargers，blowers，or（）.A . air startersB . carburetorsC . natural aspirationD . air receiver

[单选题]If the engine does not start on air, it may be due toA．low compression of the fuel pumpsB．incorrect timing of fuel pumpsC．the starting air valves stuckD．air-locks in fuel oil pipeline

[单选题]If the engine does not start on air, it may be due to （）A . low compression of the fuel pumpsB . incorrect timing of fuel pumpsC . the starting air valves stuckD . air-locks in fuel oil pipeline

[单选题]If the engine does start on air, but combustion does not immediately begin, the cause may be _____.A．failure of the fuel pumpsB．starting air pressure too lowC．stop valve in air line closedD．the turning gear still engaged

[单选题]If the engine does start on air, but combustion does not immediately begin, the cause may not be （）.A . low compressionB . failure of the fuel pump to discharge fuelC . incorrect timing of fuel pumpD . turning gear being still o

[单选题]How much is the percent of air transportation in all modes? （）A . Less than 1%B . LowestC . LowerD . Low

[单选题]H．ow often does the woman smoke?A．Quite often.B．Once in a while.C．Rarely.D．Never.

[单选题]H．ow many children does the woman have?A． Two.B． Three.C． Five.

[单选题]H．ow many generators does the shuttle carry?A．One.B．Two.C．Three.D．Four.