When the steering gear is in operation, you should （）.

If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.

The major source of chemical contaminants in hydraulic fluid is （）.

Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.

One cause of high head pressure occurring in a refrigeration system can be （）.

A salinity indicator is used to determine the （）.

The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.

The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.

Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）

If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.