A.move in an opening direction
B.move in a closing direction
C.either open or close
D.not move at all

A.help preheat the air for the furnaces
B.help preheat the feedwater
C.protect economizer from excessive heat
D.prevent excessive furnace heat losses

A.the bilges
B.the periscope
C.the water level
D.the oil pressure

A.excess stresses will not be set up in the boiler
B.the decks will not be covered with soot
C.the soot will be swept toward the uptakes
D.there will not be a loss of steam pressure

A.bottom-blow valve
B.skin valve
C.feed-check valve
D.feed-stop valve

A.a system with a Hydraulic Power Supply (HPS) unit
B.a system with roller guides for exhaust valves
C.a system with an electronically controlled Alpha Lubricator
D.a system directly powered by electric motor

A.Lower fuel consumption
B.Better balanced cylinder power
C.A shorter overhaul period
D.Less smoke emission

A.too low
B.a little lower
C.a little higher
D.exactly the same

A.a little lower
B.a little higher
C.too low
D.exactly the same

A.control fuel injection time more precisely
B.control fuel injection rate more precisely
C.meet the environmental requirements
D.meet high engine speed requirements

A.big size
B.fuel economy
C.low speed
D.high power