在不可压缩流体的稳定流动中,流动断面越大,则哪种变化的说法是正确的?()
A.流量变大,流速不变
B.流量变大,流速变大
C.流量不变,流速变小
D.流量不变,流速不变
参考答案:C
As the night is falling, a long queue stood at the bus stop, nervously expecting _______.
A. to pick up
B. picking up
C. to be picked up
D. being picked up
汽轮机开机时⑴启动油压;⑵速关油压;⑶二次油压,是按()次序建立的。
A、⑴⑵⑶
B、⑵⑴⑶
C、⑴⑶⑵
D、⑶⑵⑴