单级双吸式离心泵两侧叶轮密封环间隙不等时,会产生轴向推力。()
参考答案:对
—He should have come to join in the thorough cleaning.
—He ________, I think. It's not his turn.
A.needn't have to
B.needn't have
C.didn't have to
D.doesn't need to
根据法国现象学家()的分析,先验想象力具有开拓和后退两种功能。
A.胡塞尔
B.海德格尔
C.杜夫海纳
D.康德