环式碎煤机装有风量控制板，使入料口呈（），出料口呈微负压，能形成机内循环风，鼓风量小，粉尘小。
A、负压
B、微正压
C、平衡状态
D、正压
参考答案：B
We do our best to be careful and prevent bad things from happening,but most of us will________ find
ourselves in a situation where we or someone else needs help.
A. personally
B. obviously
C. particularly
D. eventually
剖宫产术有哪几种方式?
