The design of for a flash type evaporator is of critical importance because it must provide an optimum feedwater spray pattern that facilitates the flashing process, and it must also maintain a pressure differential between successive stages（）

A、condenser

B、flashing device

C、lashing device

D、vacuum pump

During the watch at sea （） should be logged or recorded in the engine log book.

A、the running hours of the cooling water pump

B、chief engineer’s order

C、the main parameters of main and auxiliary equipment

D、the position of the vessel

Valve cages are used on some large diesel engines to （）

A、reduce wear on the valve stem

B、permit the use of alloy valve seat materials

C、reduce heat transfer from the valve seat

D、facilitate valve removal for servicing

Late fuel injection in a diesel engine is indicated by low firing pressure with （）

A、low exhaust temperature

B、low exhaust pressure

C、mechanical knock in each cylinder

D、black or gray exhaust smoke

Before engaging the turning gear and turning the diesel engine, which of the following operation should be done except （）

A、open the indicator cocks

B、supply some LO to cylinder liner wall with lubricator

C、put the fuel handle in the stop position

D、pump up the air bottle

The over-speed trip device installed in some diesel engines is automatically actuated by（）

A、spring force

B、hydraulic pressure

C、centrifugal force

D、mechanical linkage