????:1?????????????:???????

2????????

3???????????

4???????vx

5?????????

????????????????12?????????????????????????????5?? (????????????????????? ????)???5???????????????,????????????????,????

????,??3???????????????????«?????????????»,?24????72???????,???6????????????????,?????????

?,???????????????????,??300?,??200???????????????

???????????,?????????,??????

??????3?????????,?????????4?????????1???????,????????????????????????????????6????????????4????(????????????????) ???:???????