单项选择题
A.320-400N▪m B.400-490N▪m C.490-540N▪m D.540-660N▪m
A.300-350N▪m B.350-400N▪m C.400-450N▪m D.450-500N▪m
A.20.992 B.24.614 C.23.392 D.25.718