Which of the following problems is the main source of fuel pump and injection system malfunctions?

A．Improper lubrication

B．Air in the fuel system

C．Coated fuel lines

D．Excessive vibration

[单选题]Which of the following problems can occur if you continually fail to drain off condensate from a starting air receiver?A．Corrosion and eventual failure of the tankB．Gumming of the tank relief valvesC．Immediate failure of components downstream of the

[单选题]Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?A．A shortage of liquid refrigerant.B．Excessive frost on the evaporator.C．Excessive condenser cooling water.D．Insufficien

[单选题]Which of the following problems should be taken when cleaning the air filter on a diesel engine equipped with a turbocharger? .A．Reduce engine speed to idle before removing the filterB．Soak the dirty filter in kerosene onlyC．Blow out the air inlet wi

[单选题]Which of the following problems may occur if the opening pressure of a fuel injection nozzle is greater than specified by the engine manufacturer?（）A . The amount of fuel injected will be increasedB . The start of injection will be retardedC . The no

[单选题]Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsion diesel engine?（）A . Defective temperature controls in the systemB . Cavitation in the cooling water pumpC . Opened vent in the cooling s

[单选题]Which of the following conditions will make a relation that is in first normal form. to be in second normal form?Ⅰ.every non-key attribute is functionally dependent on the full set of primary key attributes.Ⅱ.no non-key attributes exist in the relati

[单选题] Which of the following Project Scope Management processes involves subdividing the major project deliverables into smaller, more manageable components? (74)(74)A． Scope PlanningB． Scope VerificationC． Scope Change ControlD． Scope Definition

[单选题]Which of the following best represents Mr.Westhusin’s attitude toward cloning?［A］ Animal cloning is a stupid attempt.［B］ Human cloning is not yet close to getting it worked out.［C］ Cloning is too inefficient and should be stopped.［D］ Animals cloning

[单选题]which of the following plays a role in making the islands “a paradise for wildlife”?A．Animals on the islands feed on grass。B．Local government forbids killing wildlife.C．People cannot visit the islands as they wish.D．tourists are not allowed to touch

[单选题]Which of the following does the author most probably agree with?A．) The goal of the anthropologist is to understand the way in which people express themselves.B．) The anthropologist tries to understand why cultures are carried on without any change.C