单项选择题
A.boiling off
B.flash evaporation
C.condensation
D.none of the above
单项选择题 When distilling salt water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.
单项选择题 When distilling sea water the cooling water discharging from the distiller is fed back to evaporator as feed water （）.
单项选择题 In a vacuum boiling evaporator, the fresh water generated is pumped out by （）.