What is the purpose of sub cooling R-12 in the condenser?（） to increase the system efficiency by sensible heat transfer。 to stop the liquid from flashing。 to reduce the load on the compressor。 to remove latent heat of vaporization and the suction piping transfer。
城镇体系中所研究的区域经济包括哪些？是指与之对应的区域内（）的相互依存、互为作用的共生互动关系。 各产业之间。 城镇之间。 经济区之间。 环境之间。
Windows 2003的域用户账户可分为内置账户和自定义账户，下列属于内置账户的是（）。 User。 Administrator。 Guest。 Anonymou。
“四统一”操作箱一般由哪些继电器组成？
In terms of pressure and temperature in the refrigerant in the compressor, what happens to the primary?（） its pressure and temperature are both lowered。 its pressure and temperature are both raised。 its pressure is lowered and its temperature is raised。 its pressure is raised and its temperature is lowered。
客户投诉管理工作应遵循的原则是（）
