单项选择题
The feed water to the boiler will comprise （）.
A.condensate B.a small amount of make-up feed C.A and B D.None of the above
单项选择题 Proper combustion in a boiler would be indicated by （）.
单项选择题 Black smoke coming from a boiler can be caused by （）.
单项选择题 Which of the following pumps belongs to centrifugal pump?（）
