我国汉族人红细胞D抗原阴性率为()
A.0.04%
B.0.4%
C.4.0%
D.8.0%
E.40.0%
参考答案:B
同轴线采用双线扭绞的形式主要是为减少(),扭绞得越紧密抗干扰能力越好。
When workers are organized in trade unions, employers find it hard to lay them()
A.off
B.side
C.out
D.down