????:1?????????????:????vx

2????????

3????????

4????????

5???????

??2???????18? (?? ????????????????????????)????????“?”??“????????????”18???????(?)???????????????????

??“??”???“????”??????,??????????,???

????????“?????”????? ????

??????????(?)??,??????47????,??????????????????????,????431?????????

???“???????”????“???????”,??“??+??????????”?????,????????????????,?????????????????????????,????????“??”?

??????,????????,??????????????????????????????????,???“??”????,???????,?,????“?????????????”?????????

???????????????????,?????,??????????????(????)

???????????:???????