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
单项选择题 The valve that prevents water from backing out of the boiler into the feed line is the（）.
单项选择题 The mechanical exhaust valve operation system is replaced by（）in an electronic controlled ME engine.
单项选择题 （）is not a feature of the electronic controlled engines.
