活塞式压缩机转速增加时,气体的实际压缩比将()。
A.不变
B.增加
C.减少
D.大小循环变化
参考答案:A
Tom’s farther, for ________life had once been very hard, got success later in his job.
A.which
B.whose
C.whom
D.who
铜管直径D=10mm,流量Q=4.71L/min,在10m管长上的水头损失为1.918m,则其沿程损失系数是()。
A.0.03
B.0.0376
C.0.025
D.0.017