（） is the control of temperature and humidity in a space together with the circulation, filtering and refreshing of the air. Refrigeration。 Air conditioning。 Ventilation。 Heating。
一台个人计算机的内存容量为256MB，也就是其内存有（） 256兆字节。 256兆字长。 256兆比特。 256兆个字。
What is TRUE of pressure/vacuum valves? （） They are designed to provide for the flow of small volumes of tank atmospheres caused by thermal variations in a cargo tank。 They should operate in advance of the pressure/vacuum breakers。 They should be kept in good working order by regular inspection and cleaning。 All of the above。
One of the functions of ventilation is to （） the humidity of spaces containing sources of moisture, or to （） the temperature of spaces not mechanically cooled such as the engine room. increase；reduce。 reduce；increase。 increase；increase。 reduce；reduce。
占天然铀绝大部分同位素的铀-238可在下列哪些核反应堆中反应（）。 压水堆。 钠冷快堆。 气冷高温堆。 铅冷快堆。
以人民币标明面值的股票有（）
