單項選擇題

The ability of lubricating oils to resist viscosity changes during temperature changes is indicated by the（）

A.American Petroleum
B.Institute number viscosity index number
C.Seconds Saybolt Furol number
D.Seconds Saybolt Universal number

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單項選擇題

The in the steering gear move the rudder to the required angel（）

A.control equipment
B.power unit
C.transmission mechanisms
D.fittings and pipeline

單項選擇題

Positive displacement, helical gear pumps are well suited for pumping oil because （）

A.stuffing boxes eliminate the leakage problems usually associated with other gear pumps
B.it is not necessary to closely maintain design clearances with this pump
C.they are essentially self-priming and produce a high suction lift
D.these pumps are designed with extreme tooth angled