机泵噪声主要由什么产生？
参考答案：
机泵噪声主要由电机本身的电磁性噪声、尾部风机引起的空气、动力性噪声及机械噪音三部分组成。
---- Was it by cutting down staff ____ are not diligent eough _ _she saved the firm?
----- No, it was by improving work efficiency.
A．that;when
B．that;what
C．who;how
D．who ;tha
甲系吸毒成瘾人员，只有经社区戒毒后公安机关才可以对其作出强制隔离戒毒的决定。
