Chinese is used the first language in China.[ ]
A. for
B. as
C. by
D. to
答案：B
滚动轴承的组成部分？
若为生产能力利用率，抗风险能力最强的项目是( )。
A．A=90%
B．B＝70%
C．C=60%
D．D＝45%
