单选题Oil may NOT be transferred unless（）.A there are two certificated tankermen on each vesselB the vessel is equipped with constant-tension winchesC discharge containment equipment (i.e. drip pans) are in placeD All of the above

_____ they may not succeed, they will try their best.

A. Though B. When C. Because D. Unless

If you pour oil on water, it_________float.

A. shall

B. will

C. can

D. may

In a matrix organizational form, MBO may be difficult to implement:

A . If the functional employees are supervised closely by the line manager rather than the project manager

B . Unless the project manager has an input into the employee's performance review

C . Unless the project and line managers agree on the ultimate objective

D . Unless the project and line managers agree to the duration of the task

E . None of the above are correct answers

A notice of readiness is not valid unless it indicates that the vessel is ready to load or discharge as the case may be，at the time ______ it is given．

A.when

B.which

C.that

D.then

Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of ______.

A.refrigerant bubbles in the lube oil

B.refrigerant reducing the lube oil viscosity

C.oxidation(氧化) of the lube oil from overheating

D.reducing the floc or cloud point of the oil

17．_________they may not succeed，they will try their best．

A．Though

B．When

C．Because

D．Unless

第二组

Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.

Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.

To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.

The passage is mainly about

A.crankcase explosion

B.scavenge box fire

C.starting air pipe

D.the danger of explosion in the starting air system

174 In a matrix organizational form, MBO may be difficult to implement:

A. If the functional employees are supervised closely by the line manager rather than the project manager

B. Unless the project manager has an input into the employee's performance review C. Unless the project and line managers agree on the ultimate objective

D. Unless the project and line managers agree to the duration of the task

E. None of the above are correct answers

A hydraulic motor may be driven by______.

A.an electric motor

B.a diesel engine

C.a compressor

D.oil

Oil may NOT be transferred unless ______.

A.there are two certificated tankermen on each vessel

B.the vessel is equipped with constant-tension winches

C.discharge containment equipment (i.e. drip pans) are in place

D.All of the above