永久气体气瓶充装系统用的压力表,精度应不低于( )级,表盘直径应不小于( )mm。
A.1.5;150B.1.0;100C.1.0;200D.1.5:100
参考答案:A
______ which university to attend, the girl asked her teacher for advice.
A.Not knowing
B.Knowing not
C.Not known
D.Known not
为减少电压偏差,供配电系统的设计应合理减少系统阻抗。()