A．9/5 B．27/5 C．15/9 D．9/15
单项选择题3×5, 5×7, 7×11, 11×13, 13×17, ( )
单项选择题1, 4, 27 4( )12 16 27 4
单项选择题1, ( ), 3, 10, 29, 66
单项选择题( ), 10, 18, 28, 40, 54
