The condensers located in various stages of a flash evaporator are cooled by（）

Which of the following items don’t belong to dock repair works?（）

During the diesel engine running, the water level of F.W expansion tank should normally kept in the （） level of glass tube.

（）connectors hold best if a wire is accidentally pulled or a connection becomes loose.

If separating effect is not good, which measure should be taken （）

A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）

Cold weather starting of a diesel engine may be made easier by（）

One of the reasons that cause oil flowed from sludge outlet of a self-cleaning separator is（）

The treatment of the fuel oils involves storage, heating, filtering and（）

The main purpose of port State control is not to（）