以下哪一项不是K3系统的生产类型属性()
A.普通订单
B.委外加工
C.重要订单
D.重复生产
参考答案:C
正常人血中HCO3-与H2CO3之比为()
A.15:1
B.10:1
C.20:1
D.25:1
E.30:1
VHF radio is one of the very important navigational instruments on board,()messages can be sent.
A.by which
B.through which
C.by that
D.through that