单项选择题
A pump is defined as device that（）
A.produces pressure B.imparts energy to a fluid to move it from level ‘A’ to level ‘B’ C.creates a vacuum to move a liquid in all installation D.is to develop a pressure differential
单项选择题 A distorted furnace in a fire-tube auxiliary boiler may be the result of （）
单项选择题 Fins are installed on the fireside of water-tubes used in waste boiler to（）
单项选择题 A smoking burner with a pulsating flame in auxiliary boiler, is an indication that the（）
