过滤开始时，滤浆在（）的压力作用下，经止推板的进料口进入各滤室内。
参考答案：进料泵
Sally was a bit shy, but we found her quite ____ discussing recent singing stars with others.
A．at home
B．at a loss
C．in public
D．in common
空调管道采用螺纹连接时，管道螺纹应符合哪些要求？
