离心泵的过流部件是指泵的吸人和排出口、吸入室、压出室以及（）。
A、叶轮
B、轴套
C、密封环
D、联轴器
参考答案：A
________him that she would fail as she was so able and worked so hard.[ ]
A．It never occurred to
B．That never occurred to
C．It never occurred with
D．That never occurred for
舒茨以人际需要为主线所提出的理论是（）。
A.人际交往的三维理论
B.人际交往的需求理论
C.人际交往的关系理论
D.人际交往的价值理论
E.人际交往的动机理论
