一般而言,下列影响利润变动的各因素中,利润对( )因素的敏感程度最大
A.销售单价
B.单位变动成本
C.固定成本总额
D.销售量
参考答案:A
— Is your father still teaching?
— Yes. It's about sixteen years ______ he started teaching. [ ]
A. until
B. after
C. since
D. with
木脚手架横杆有效部分小头直径不得小于()毫米。