单项选择题
The water level in a steaming auxiliary boiler will always （）
A.rise when the steam pressure is increased B.remain constant as long as the feed pump operates C.fall when the steam pressure is decreased D.vary as the steam demand changes
单项选择题 The donkey boiler may be given a bottom blow （）
单项选择题 When steam is being raised on a boiler, the water level will normally （）.
单项选择题 The furnace of an oil fired boiler should be （） before the operating burner is lit.
