什么叫真空蒸发制盐操作“五稳定”?
参考答案:
①首效加热室进汽压力稳定。
②末效真空度稳定。
③各效液位稳定。
④各效罐内固液比稳定。
⑤班产量稳定。
There a lot of farmland here. But now you can only see tall buildings. [ ]
A. used to have
B. is used to being
C. used to having
D. used to be
救生艇起艇绞车,左右舷梯绞车,防火绳绞车均由液压泵系统控制。