Stuck with string replacement

Sub Main
    Dim statement As String = "INSERT INTO X (a,b,c) values (?,?,?)"
    Dim statements As String() = statement.Split("?"C)

    'Construct a stringbuilder
    Dim sb As New StringBuilder()
    For i As Integer = 0 To statements.Length - 2
        sb.AppendFormat("{0}@param{1}", statements(i), i + 1)
    Next
    sb.Append(statements(statements.Length - 1))

    Dim modifiedStatement As String = sb.ToString()
    Console.WriteLine(modifiedStatement)

End Sub
'Output
'INSERT INTO X (a,b,c) values (@param1,@param2,@param3)