丙烯制冷压缩机系统不控制四段吸入温度，因为进10-V-504的气相中混合有来自（）的液相丙烯。
参考答案：丙烯冷剂收集罐
The farmers in the fields when it to rain.[ ]
A. worked;was began
B. were working;began
C. were working;was beginning
D. worked;began
新时期党和国家培养少数民族干部的方针政策是什么？
