一般情况下二次安全检查的间隔时间为（）个月。
A.12
B.8
C.6
D.3
参考答案：C
Buying clothes a hard job because the clothes a person likes not very often fit him or her.
A．are: d0
B．is; does
C．are; does
D．is; do
TR
A．相对迁移率(Rm)B．比移值(Rf值)C．分配系数D．容量因子E．保留时间
