______ is another way of saying "fall". [ ]
A. Spring
B. Summer
C. Autumn
D. Winter
答案:C
离心式水泵二级保养时,要检查联轴器的同心度,径向允许误差为()。
A.0.5mm
B.0.10mm
C.0.35mm
D.1.0mm
DEH系统的操作主要有哪些?