长管并联管道,若管长、管径、粗糙度均不相等,但其下述哪个因素相等?()
A.水头损失相等
B.通过流量相等
C.总的能量损失相等
D.水力坡度相等
参考答案:A
The concert ______ next Thursday and we will enjoy the best performance from the best pianist.
[ ]
A. happens
B. breaks out
C. comes about
D. takes place
产品的质量的好坏是靠检查出来的。()