?? ??????????????????“??”
????:1??????????:?????????
2???????vx
3??????????
4??????????????
5????????
?9???19?? (??? ???)???????????9???19????????????????,????????“???”(Sigma Geography),????
9??????????????19?????????,??“??????????????????”???????????????????? ????? ??????????????????????????,???????????,????????????????????????????,?“????????????????”????????????????????“?????”“??????????”“?”“?????????”????????????????????????????????,????????????
???,“??”?????,???????????????????(???)
?????????:???