问题：
[单选] A variable pitch propeller is made （） a boss with separate blades mounted into it.
of。up of。from。out。
问题：
[单选] A: Please tell me the specifications and quantity. B: （）
Pump diesel oil first。300 tons of 180 cst fuel oil。The figure is all right。OK, I’ll sign it。
问题：
[单选] About half an hour before the engine is required, cooling water at （） must be circulated.
more than the working temperature。less than the working temperature。the working temperature。the same as the surrounding temperature。
问题：
[单选] According to the way the energy of the exhaust gases is utilized, pressure-charging can be divided into two main systems, namely, the constant-pressure system and （）.
the pulse-phase system。the pulse Doppler system。the pulse system。the pulse interval。
问题：
[单选] Acid solution（） in the system can be tested from time to time by putting some on to a piece of lime.
strength。dense。percentage。velocity。
问题：
[单选] Additives （） protective layers on metal surfaces guarding them against corrosion.
damage。form。dissolve。contaminate。
问题：
[单选] Adjust （） by means of lead wire.
the clearance of the main bearing。the diameter of main bearing。the gap of main beating。the tolerance of main bearing。
问题：
[单选] Administrations should bear in mind the significance of （） in maintaining safety of life and property at sea and in preventing marine pollution.
advanced nautical equipment。advanced performance main engines。emergency equipment。communication and language skill。
问题：
[单选] A-frames and cylinder block is held together by （） to form a rigid structure.
connecting rods。piston rods。tie rods。jack-bolt。
问题：
[单选] A-frames are mounted on the bed plate and support （） and cylinder block.
the main bearing。the cylinder cover。the entablature。the sum。
