?? ?????Χ2!????????????
????:1??????????:??????
2????????????
3?????
4?????????
5?????
?????????(19?)??????????,????????????????????,???
?????????????????????????????,????428??,??????5????
???????90??,????3.7??,???6????????,?????????????5600????
?1996?3?????,??,???324???,????1.6?????????????28???,?2300????
??,??????,????32???????,????????????????????????????2700??
(???? ?? ??????????? ????????) ??:???????????????