单项选择题
A.yellowish flame
B.golden yellow flame
C.milky flame
D.brilliant white flame
单项选择题 As for an oil-fired boiler if at a normal steaming condition and water goes out of sight in gauge glasses the action you should take is: （） (1) secure oil to fires (2) increase feed pump pressure
单项选择题 The amount of heat released by steam when it changes to water at the same temperature is called（）.
单项选择题 Latent heat changes the （） of water.