某公务员的职务为副科长，他的级别在：

A．9-13级范围内

B．10-13级范围内

C．9-14级范围内

D．9-12级范围内

Bill is _____ English. He is not _____ Chinese boy. [ ]

A. /; a

B. /; an

C. an; the

D. an; a