50×12÷13,
=25÷13,
=75(千克),
答:75千克的13是50千克的12一样.
—Will you be able to finish your report today?
—________. [ ]
A. I like it
B. I hope so
C. I'll do so
D. I'd love it
泵与风机的主要性能参数有()
A.流量与扬程
B.转速
C.功率与效率
D.汽蚀余量