齿轮泵的流量一般与转速成正比,但转速过高,由于离心力的作用,液体不能充满整个齿间,反而使流量减少并引起()。
参考答案:气蚀
____ I admire David as a poet, I do not like him as a man.
A.Only if
B.If only
C.As much
D.Much as
我国水土流失最为严重的地区是[ ]
A.黄土高原
B.山东丘陵
C.江南丘陵
D.云贵高原