压滤机头板压力一般控制在（）MPa。
A、4-8
B、8-14
C、14-16
D、16-18
参考答案：B
.
---Putting on a happy face not only helps us make friends but also makes us feel better.
--- ________.
A．I’d love to.
B．I’m with you on that.
C．It’s up to you .
D．It’s my pleasure.
怎样扑救电气火灾？
