单项选择题
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
What is the first thing you would check on taking over ...
单项选择题What is the first thing you would check on taking over a watch?（）
A.the bilges B.the periscope C.the water level D.the oil pressure
Soot blowers should be used in proper sequence so that（...
单项选择题Soot blowers should be used in proper sequence so that（）
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
The valve that prevents water from backing out of the b...
单项选择题The valve that prevents water from backing out of the boiler into the feed line is the（）.
A.bottom-blow valve B.skin valve C.feed-check valve D.feed-stop valve
