，I have never seen anyone who's as capable as John.

A．As long as I have traveled

B．Now that I have travelled so much

C．Much as I have traveled

D．As I have traveled to much

我国基本医疗保险费由用人单位和职工共同缴纳，用人单位的缴费率应控制在职工工资总额的 ( )左右。

A．2%

B．4%

C．6%

D．8%