瞬态液动力
参考答案:
瞬态液动力是指,在阀芯运动过程中,阀开口量变化使通过阀口的流量发生变化,引起阀腔内液流速度随时间变化,其动量变化对阀芯产生的反作用力。
It was because of his absence _____ the meeting had to be put off. [ ]
A. so
B. so that
C. why
D. that
英国 * * 运动的基本要求和历史意义。