The time required to incline from bow down to stern down and return to bow down again is called（）.

A requirement is simplya statement of what the system must do or what characteristics it needs to have. Requirements written from the perspective of user and focus on user needs are called _( )_.

The consignee’s refusal to take delivery，or failure to do so within a reasonable time，also puts an end to（）liability as a carrier.

When to remove scale from the cooling spaces, acid solution （） in the system can be tested from time to time by putting some on to a piece of lime.

60.  A from time to time   B  in time    C  sooner or later   D on occasion

Which of the following do not belong to the same type according to the manner or place of articulation?  

（） provides the head or pressure to supply the domestic water where required.

The consignee’s refusal to take delivery，or failure to do so within a reasonable time，also puts an end to（）liability as a carrier.

When installed for bilge pumping or ballast duty, centrifugal pumps require a （） to remove air from the suction pipe.

It is the ability to do the job ______ matters not where you graduate from or what you are.

（） system is arranged to ensure that water can be drawn from any tank or the sea and discharged to any other tank or the sea as required to trim the vessel.

When pushing ahead，wires leading from the quarters of the after outboard barges to the bow of a towboat（）.