单项选择题 What is the function of thermostatic expansion valve in a compression refrigeration system?（）

单项选择题 In a compression refrigeration plant the hot, high pressure refrigerant gas is cooled by the sea water and becomes liquid in the （）.

单项选择题 In the （） refrigeration compressor one end of the crank shaft extends through the crankcase house for connection, via a coupling or pulley, to an external drive motor.