什么是韧皮部装载？
In the refrigeration system, a shortage of refrigerant is indicated by （）. the compressor short cycling on high pressure cut out switch。 high suction pressure。 high head pressure。 bubbles in the sight gla。
铜管宜采用牌号为（）的管材。
什么是安全监察？安全保证和安全监察之间的关系是怎样的？
Which of the following conditions must exist for heat to flow from one object to another?（） The two objects must be in physical contact。 The two objects must be the same size。 There must be an existing temperature differential。 There must be an existing weight differential。
依照《行政复议法》及其《实施条例》的规定，申请行政复议的公民、法人或者其他组织为（）
