单项选择题
A.capability of causing brittle fractures
B.highly corrosive action on mild steel
C.vapor cloud which reacts violently with saltwater
D.toxicity at atmospheric pressure
单项选择题 The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by （）.
单项选择题 In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the（）.
单项选择题 The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs, is to （）.