Most conducting materials such as copper, aluminum, iron, nickel, and tungsten （）.

A、increase in resistance with increased temperature

B、increase in resistance with decreased temperature

C、decrease in resistance with increased temperature

D、increase in conductance with increased temperature

Which of the following problems will occur if the internal drain at either end of a hydraulic, two-way, spool-type directional control valve cylinder were to become plugged?（）

A、The reservoir would become vapor bound

B、The valve would be placed in hydraulic lock

C、The spring loaded relief ports would open

D、The buffering chambers would be unable to function

When oily water separator is operating, which measure （） is wrong.

A、pay attention to operating parameters

B、renew and clean separating units in time

C、check oil level in separator to prevent overload

D、check separating effect, if it is bad, flush with large capacity water pump

The load between two steam-driven alternators operating in parallel may be adjusted by varying （）

A、the speed of the alternators

B、the field strength of the machines

C、the power factor of the alternators

D、steam supply to the prime movers

Basically the bedplate consists of two （）, which run the length of the engine.

A、longitudinal girders

B、transverse girders

C、fore girders

D、aft girders

Most marine biological sewage treatment plants consist of all the following statements except （）.

A、aeration tanks

B、settling tanks

C、disinfection agent

D、anaerobic bacteria